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ISBN10: 5932861037ISBN13: 9785932861035

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Cover_javascript_new.qxd 22.02.2008 12:43 Page 1

David Flanagan

The Definitive Guide

Fifth Edition

2008

JavaScript. , 5

. . . . . . . .

.JavaScript. . . . : ,2008. 992 ., .ISBN10: 5932861037ISBN13: 9785932861035

JavaScript. . HTTP Ajax, XML, , JavaScript, , , , Flash JavaScript Java. I JavaScript. II , . , HTML, DHTML, , Ajax, XPath XSLT XML, Ajax. III JavaScript (, , , , , , JavaScript 1.5 ECMAScript v3). IV JavaScript (API , DOM API Level 2 : XMLHttpRequest ).

ISBN10: 5932861037ISBN13: 9785932861035ISBN 0596101996 ()

, 2008Authorized translation of the English edition 2006 OReilly Media, Inc. This translation is published and sold by permission of OReilly Media, Inc., the owner of allrights to publish and sell the same. , . , , .

. 199034, , 16 , 7,. (812) 3245353, www.symbol.ru. N 000054 25.12.98.

00593, 2; 953000 .

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199034, , 9 , 12.

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1. JavaScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

1.1. JavaScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211.2. JavaScript. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211.3. JavaScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231.4. JavaScript. . . . . . . . . . . . . . . . . . . . . . . . . . 281.5. JavaScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

I. JavaScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

2.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . 342.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362.8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

3.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 513.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 533.7. null. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 553.8. undefined . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 553.9. Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 563.10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 563.11. Error. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 573.12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 573.13. . . . . . . . . . . . . . . . . . 58

8

3.14. . . . . . . . . . . 603.15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

4.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 674.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 684.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 694.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 714.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 734.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 744.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

5.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 775.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 785.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 815.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 835.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 865.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 885.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 895.8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 915.9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 925.10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

6.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 996.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1006.3. if . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1016.4. else if . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1026.5. switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1036.6. while. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1056.7. do/while . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1066.8. for. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1076.9. for/in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1086.10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1096.11. break . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1106.12. continue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1116.13. var . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1126.14. function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1136.15. return. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1146.16. throw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1156.17. try/catch/finally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1166.18. with . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1186.19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

9

6.20. JavaScript. . . . . . . . . . . . . . . . . . . . . . . . 119

7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

7.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1227.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1237.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1257.4. Object . . . . . . . . . . . . . . . . . . 1277.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1297.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1307.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1337.8. , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

8.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1398.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1438.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1488.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1508.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1528.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1528.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1548.8. . . . . . . . . . . . . . . . . . . . . . . . . 1568.9. Function() . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

9. , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1659.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1669.3. JavaScript . . . . . . . . . . . . . . . . . . . . . . 1729.4. Object. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1789.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1829.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1869.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1899.8. : defineClass() . . . . . . . . . . . . . . . . . . . . . 194

10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

10.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . 19910.2. . . . . . . . . . . . . . . . . . . . . . . . . . . 20410.3. . . . . . . . . . . . . . . . . . . . . . . . 208

11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214

11.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . 21411.2. String . . . . . . . . . . . . . . . . . . . . 22311.3. RegExp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

10

12. Java . . . . . . . . . . . . . . . . . . . . . 229

12.1. JavaScript. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22912.2. Java . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

II. JavaScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249

13. JavaScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251

13.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25213.2. JavaScript HTML . . . . . . . . . . . . . . . . . 25813.3. HTML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26413.4. JavaScript URL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26613.5. JavaScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26813.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27313.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27913.8. JavaScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28013.9. JavaScript . . . . . . . . . . . . . 285

14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

14.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28814.2. Location History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28914.3. Window, Screen Navigator . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29114.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29714.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30214.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30314.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30414.8. . . . . . . . . . . . . . . . . . . . . . . . 30614.9. : . . . . . . . . . . . . . . . . . . . . . . . . . . . 311

15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314

15.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . 31515.2. Document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31715.3. DOM:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31915.4. W3C DOM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32315.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33415.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33515.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33915.8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34315.9. : . . . . . . . . . . . . . . . . . . . . . 35115.10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35615.11. IE 4 DOM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 357

11

16. CSS DHTML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360

16.1. CSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36116.2. CSS DHTML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37016.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38616.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39516.5. CSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39616.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397

17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403

17.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40417.2. DOM Level 2 . . . . . . . 41417.3. Internet Explorer . . . . . . . . . . . . . . . . . . . . . 42517.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43517.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44017.6. onload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44917.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450

18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453

18.1. Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45418.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45518.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45918.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 467

19. Cookies . . . . . . . 472

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21. JavaScript XML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518

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'lowerRight': { x:(point.x + side), y:(point.y+side) }};

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, .

3.6. (array), , . , , , , . JavaScript , , . , a , i , a[i] . , . . a[2] a.

JavaScript, . :

54 3.

document.images[1].width

width , , images document.

: (. 3.5). , . . , JavaScript ( ). , JavaScript , , , Java. 7.

3.6.1. Array(). :

var a = new Array();a[0] = 1.2;a[1] = "JavaScript";a[2] = true;a[3] = { x:1, y:3 };

Array(). , :

var a = new Array(1.2, "JavaScript", true, { x:1, y:3 });

Array() , . , 10 :

var a = new Array(10);

3.6.2. JavaScript . , , , . , ., , , :

var a = [1.2, "JavaScript", true, { x:1, y:3 }];

, :

var matrix = [[1,2,3], [4,5,6], [7,8,9]];

, :

var base = 1024;var table = [base, base+1, base+2, base+3];

3.7. null 55

, . , :

var sparseArray = [1,,,,5];

3.7. null null JavaScript . , null . null . null,, , , , .1

null , false, 0, "null".

3.8. undefined , JavaScript, undefined. , , , , . , undefined , null.

null undefined , == . :

my.prop == null

, my.prop , , null. null undefined , , . null undefined, === typeof ( 5).

null, undefined JavaScript. ECMAScript v3 , undefined, undefined. , , , undefined , .

, undefined, :

var undefined;

1 C C++ , null JavaScript , 0, . null 0, .

56 3.

, , , undefined. void (. 5) undefined.

undefined , false. NaN, "undefined".

3.9. Date , JavaScript. , JavaScript , , . Date JavaScript new Date() ( new 5, 7 ):

var now = new Date(); // , .// , .// : , 11!var xmas = new Date(2000, 11, 25);

Date , (GMT). :

xmas.setFullYear(xmas.getFullYear() + 1); // .var weekday = xmas.getDay(); // 2007 .document.write(": " + now.toLocaleString()); // .

Date ( , Date) , , , .

Date .

3.10. . . JavaScript Perl.

JavaScript RegExp RegExp(). Date, RegExp JavaScript; , JavaScript.

Date, RegExp JavaScript. .

3.11. Error 57

, . :

/^HTML//[19][09]*//\bjavascript\b/i

11. , JavaScript.

3.11. Error ECMAScript v3 . JavaScript . ( 6 throw try.) message, . Error, EvalError, RangeError, ReferenceError, SyntaxError, TypeError URIError. .

3.12. , , . : , , JavaScript . , , , . , . , JavaScript . . 3.3 , , .

3.3.

,

"undefined" NaN false Error

null "null" 0 false Error

NaN

true String

0 false String

0 "0" false Number

NaN "NaN" false Number

58 3.

3.3 ()

3.13. , : .1 , :

var s = "These are the times that try people's souls.";

var last_word = s.substring(s.lastIndexOf(" ")+1, s.length);

, , s , .

? ? typeof (. 5) , , . ?

, . , JavaScript Number, String Boolean. . (wrapper) , , .

JavaScript . , . . , JavaScript . String . ,

,

Infinity "Infinity" true Number

Infinity "Infinity" true Number

true Number

true "true" 1 Boolean

false "false" 0 Boolean

toString() valueOf(),toString() NaN

true

1 , .

3.13. * 59

. , , ; , .

, String, , , , , . , s , :

var len = s.length;

s , . String, length, , s. , , . JavaScript , .

String , , . String , , new. :

var s = "hello world"; //

var S = new String("Hello World"); // String

S String? , . typeof, , S , , , String.1 , String, . , . String , , JavaScript String . , String +, :

msg = S + '!';

, , String, Number Boolean. .

, , , Object():

var number_wrapper = Object(3);

1 eval() String, String , , .

60 3.

3.14. , 3.5.3. .1

, true. ( ), , , false. , true :

new Boolean(false) // false, truenew Number(0)new String("")new Array( )

. 3.3 , valueOf(). valueOf() Object, . valueOf() , JavaScript toString() .

. toString() , . , , 0! , , n, n, n. , NaN.

, . , . + (=) , , , , : . JavaScript valueOf(). ( , ), . valueOf() , JavaScript toString().

1 , .

3.15. 61

: + Date, toString(). , Date toString() valueOf(). Date +, , , .

valueOf(), . +, . , , , .

, valueOf(), . valueOf(), , , , valueOf() , toString() . , valueOf().

, , valueOf() toNumber(). , , ; valueOf() .

3.15. JavaScript, , .1 . , . . , , . , .

: ' . , , . , , . , . , , . , . , ,

1 , .

62 3.

( , ).

. , .1 , , . , . , , . , . . , . , . , . . , , , , . , (. . ), .

, . . 3.4 . , , , . , JavaScript. , , .

3.4.

1 C , , . , JavaScript .

.

. , .

. .

. , .

3.15. 63

3.15.1. JavaScript : ' , , , . JavaScript. , , JavaScript. . . , , , . , .

? , . JavaScript , . . .

, , . , . 3.1 , . , , .

3.1. ,

//

var n = 1; // n 1

var m = n; // : m 1

//

// , ,

function add_to_total(total, x)

{

total = total + x; // total

}

// , ,

// n m. n

// total. m n,

( ), , .

, , . , .

64 3.

// n. // n .// , .add_to_total(n, m);

// .// 1 // , "" . // , n. , // , .if (n == 1) m = 2; // n , 1; // m 2

3.2. , . , . Date, .

3.2. ,

// , 2007 // xmas , var xmas = new Date(2007, 11, 25);

// , var solstice = xmas; //

// solstice.setDate(21);

// xmas.getDate( ); // 21, 25

// .// .// , .// , // , .function add_to_totals(totals, x){ totals[0] = totals[0] + x; totals[1] = totals[1] + x; totals[2] = totals[2] + x;}

// , .// , , , // , // , :(xmas == solstice) // true

// , , , // .var xmas = new Date(2007, 11, 25);var solstice_plus_4 = new Date(2007, 11, 25);

// " "

3.15. 65

// !

(xmas != solstice_plus_4) // true

, . . , . . , , . , . , , , , , , . 3.3 .

3.3.

// add_to_totals(). ,

// .

function add_to_totals2(totals, x)

{

newtotals = new Array(3);

newtotals[0] = totals[0] + x;

newtotals[1] = totals[1] + x;

newtotals[2] = totals[2] + x;

totals = newtotals; //

//

}

3.15.2. , . , , . , . , . , , .

, JavaScript . , , , .

: JavaScript . charAt(), , setCharAt(), . . JavaScript

66 3.

JavaScript , .

, , . . , . , JavaScript , , , .

3.15.3. , , , JavaScript, , . 3.4 , .

3.4. , ?

// , , , // . , // . // , , // , :var s1 = "hello";var s2 = "hell" + "o";if (s1 == s2) document.write(" ");

, . , C, C++ Java, . . JavaScript , , , . , , JavaScript () , .

3.15.4. : 3.5 , JavaScript.

3.5. JavaScript

, . , , , . . , JavaScript 2 i:

i = 2;

3 i sum:

var sum = i + 3;

, . JavaScript , ! ,, , , /.1

4.1. JavaScript , Java C, , JavaScript (untyped) . , , JavaScript , Java C, , . , JavaScript , :

i = 10;i = "";

1 , . 5, 6 7, .

68 4.

Java, C, C++ .

JavaScript, , , . , , JavaScript , . 3.

JavaScript , C++ Java, , , , . JavaScript , , .

4.2. JavaScript, .1

var :

var i;

var sum;

:

var i, sum;

, :

var message = "hello";

var i = 0, j = 0, k = 0;

var, , (undefined), .

, var for for/in ( 6), . :

for(var i = 0; i < 10; i++) document.write(i, "");

for(var i = 0, j = 10; i < 10; i++, j) document.write(i*j, "");

for(var i in o) document.write(i, "");

, var, ' (permanent): delete . ( delete 5.)

1 , JavaScript.

4.3. 69

4.2.1. var . , .

, JavaScript . , var, JavaScript . , , , . ( ), , var . var , . ( .)

4.3. (scope) , . JavaScript. , , . ' . , .

. , , . , :

var scope = ""; //

function checkscope() { var scope = ""; //

document.write(scope); // ,

}checkscope(); // ""

, var , . , , :

scope = ""; // , var

function checkscope() {

scope = ""; // ! document.write(scope); //

myscope = ""; //

document.write(myscope); // }

checkscope(); // ""

document.write(scope); // ""document.write(myscope); // ""

70 4.

, , , . , , , . , : var.

. , . :

var scope = " "; // function checkscope() { var scope = " "; // function nested() { var scope = " "; // // document.write(scope); // " " } nested();}checkscope();

4.3.1. : C, C++ Java, JavaScript . , , , , . i, j k : . , C, C++ Java:

function test(o) { var i = 0; // i if (typeof o == "object") { var j = 0; // j , for(var k = 0; k < 10; k++) { // k , document.write(k); } document.write(k); // k : 10 } document.write(j); // j , }

, , , , . :

var scope = "";function f() { alert(scope); // "undefined", "". var scope = ""; // , // . alert(scope); // ""}f();

, alert() , . . var,

4.4. 71

, . . , , . , var . f :

function f() { var scope; // alert(scope); // , undefined scope = ""; // alert(scope); // }

, .

4.3.2. JavaScript: . , . ' . , . , .

, , . , undefined. (unassigned), , .

:

var x; // . undefined.alert(u); // .u = 3; // .

4.4. , , . , . ? , , , , JavaScript. : .

, , null undefined . , .

. , , .

72 4.

. JavaScript , .1

. , . : . JavaScript. , , . . . , , .

, . . . , ( ):

var a = 3.14; // var b = a; // a = 4; // alert(b) // 3.14;

. , , , ( ):

var a = [1,2,3]; // var b = a; // a[0] = 99; // , alert(b); // [99,2,3],

, , . , , . , , . ; .

, . , . 3.15.

, , JavaScript . . , , . , JavaScript , . . , ,

1 , JavaScript.

4.5. 73

, , . . : . , , , . , , , , , , .

4.5. ; , . , . , . .

, , , . JavaScript , , . , , , JavaScript , .

, C C++, . , , ( ). .1

JavaScript, , , (garbage collection). JavaScript , ., (. . ), , , .2 :

var s = "hello"; // var u = s.toUpperCase(); // s = u; //

"hello" . .

1 : ( ) , , , . STL, . , new delete. . . .

2 , , . Perl; . . . . .

74 4.

. , , , , .

4.6. , JavaScript . , JavaScript . . i i o? : . JavaScript .

4.6.1. , JavaScript , . JavaScript. JavaScript , .

JavaScript , . , Infinity, parseInt Math , parseInt() Math. .

(. . JavaScript, ) this. this , 8.

JavaScript JavaScript, , Window. window, , this . Window , parseInt Math, , navigator screen.

4.6.2. , ? . (call object). , . JavaScript .

4.6.3. JavaScript , JavaScript (execution context), . . ,

4.7. 75

JavaScript. , . JavaScript, , , . JavaScript , .

, JavaScript .1

( .) JavaScript, . JavaScript . , . , JavaScript parent.frames[1], x parent.frames[0].x.

, JavaScript. JavaScript 13. , JavaScript JavaScript .

. JavaScript , , . JavaScript. , A , B . , B A. , , ., JavaScript , , . 13.8.

4.7. , JavaScript: , , , .

1 ; , .

76 4.

, , , . , , , , . , JavaScript.

JavaScript ' (scope chain), , , . JavaScript x ( ), () . x, . x, JavaScript . x, , . .

JavaScript ( , ), . . , undefined. ( ) . , ( ), ( ). . . 4.1.

. 4.1.

, JavaScript., C, C++ Java, , JavaScript , . , C, C++ Java, , JavaScript.

5.1. JavaScript, . , :

1.7 // "JavaScript is fun!" // true // null // null/java/ // { x:2, y:2 } // [2,3,5,7,11,13,17,19] // function(x){return x*x;} // i // isum // sum

. , , , .

. ( ) . , , 1.7 , i . :

i + 1.7

78 5.

. + , . (), . :

(i + 1.7) sum

sum , i + 1.7. , JavaScript , + .

5.2. C, C++ Java, JavaScript . . 5.1, . : , + =, , delete instanceof. , , .

, P, , , A, ( L , R ). , , , , .

5.1. JavaScript'

P A

15 L . ,

L [] ,

L () ,

R new

14 R ++

()

R

()

R ( )

R + ( )

R ~ ()

R ! ()

R delete

()

R typeof ()

5.2. 79

5.2.1. . JavaScript, +, , . , . , . JavaScript ,

R void ()

13 L *, /, % , ,

12 L +, ,

L +

11 L >

L >>>

10 L = ,

L instanceof ,

L in ,

9 L ==

L !=

L ===

L !==

8 L &

7 L ^

6 L |

5 L &&

4 L ||

3 R ?: , ,

2 R = ,

R *=, /=, %=, +=,=, =,>>>=, &=, ^=, |=

,

1 L ,

P A

80 5.

, . 3 , 3. , JavaScript , ?:, .

5.2.2. JavaScript, , , , . , . , , "a" * "b" JavaScript. JavaScript , "3" * "5" . 15, "15". JavaScript 3.12.

. +, . , , . , "1" + 0 "10".

, , , (lvalue). , , . JavaScript , . ECMAScript , , .

, , . (, , . .) , , , . , a < 3 true, a , 3. , , , if, while for, JavaScript .

5.2.3. . 5.1 , P, . , . P , , .

:

w = x + y * z;

5.3. 81

* +, . , = , .

. , :

w = (x + y)* z;

, , . : , .

5.2.4. . 5.1 , A, . L , R . . , . , , :

w = x + y + z;w = ((x + y) + z);

( ) :

x = ~~y;w = x = y = z;q = a?b:c?d:e?f:g;

:

x = ~((~y));w = (x = (y = z));q = a?b:(c?d:(e?f:g));

, , .

5.3. , , . :

(+)

. , .

82 5.

, . valueOf() / toString().

()

, . , .

(*)

* . .

(/)

/ . . , , , . JavaScript , . 5/2 2.5, 2. , 0/0 NaN.

(%)

% , . , . , 5 % 2 1. , . , 4.3 % 2.1 0.1.

()

, . , , . , .

(+)

JavaScript . , , :

var profit = +1000000;

; . . , NaN.

(++)

(. . ) , , . , ,

5.4. 83

. . ( ), 1, . ( ), 1, . , . , i j 2:

i = 1;j = ++i;

i 2, j 1:

i = 1;j = i++;

, . : , JavaScript . , JavaScript .

()

(. . 1) , , . , , . ++, . , , , .

5.4. . , (true false) . 6, if for .

5.4.1. (==) (===) == === , . true, , false, . ===, , , . == , , , .

84 5.

ECMAScript v3 JavaScript 1.3 . JavaScript =, == ===. , , . ! , = , , == , ===.

JavaScript , '. , == === , . , , . , , .

, . , , . , . , , , , , . , , . ( , , .)

=== :

, . , ,

NaN ( , ). NaN , ! , NaN, isNaN().

, . , . , Unicode . JavaScript , , . III String.localeCompare().

true false, .

, , . ( ), , .

5.4. 85

null undefined, .

==:

, . , ; , .

, . :

null, undefined, . , ,

.

true, 1 . false, 0 .

, , . toString(), valueOf(). JavaScript valueOf(), toString(), Date, toString(). , JavaScript, , .

.

:

"1" == true

true, . . . true 1, . "1" 1. , true.

5.4.2. (!=) (!==) != !== , == ===. != false, , true . !== false, , true . ECMAScript v3 JavaScript 1.3 .

, ! . , != , !== . .

86 5.

5.5. JavaScript. , ( ) true false , . 6, if while .

5.5.1. . :

()

> true, , ; false.

(= true, ; false.

. , , , . :

, .

, .

, , . , NaN false. ( JavaScript 1.1 NaN, .)

, , JavaScript . , , Date , . . , .

, false.

5.5. 87

NaN, false.

, , Unicode. Unicode , JavaScript ; , . : , . . Unicode ( , ASCII) . . , < "Zoo" "aardvark".

String.localeCompare(), . String.toLowerCase() String.toUpperCase().

= ( ) . , . , NaN ( ); false.

5.5.2. in in , . ( ). true, , . :

var point = { x:1, y:1 }; //

var has_x_coord = "x" in point; // true

var has_y_coord = "y" in point; // true

var has_z_coord = "z" in point; // false;

var ts = "toString" in point; // ; true

5.5.3. instanceof instanceof , , . true, , , , ; false. 9 , JavaScript ., instanceof . : Object. :

var d = new Date(); // Date()

d instanceof Date; // true; d

// Date()

88 5.

d instanceof Object; // true;

// Object

d instanceof Number; // false; d Number

var a = [1, 2, 3]; //

a instanceof Array; // true; a

a instanceof Object; // true;

a instanceof RegExp; // false;

instanceof , , instanceof false. , .

5.6. , , , .

+ . , , , . , "hello there":

"hello" + " " + "there"

"22":

a = "2"; b = "2";

c = a + b;

= , . . 5.1.1, JavaScript Unicode. , ( ), .

== != , , , , .

+ , . , + ( ), ( ) , . , , . , JavaScript . :

1 + 2 // . 3.

"1" + "2" // . "12".

"1" + 2 // ; 2 "2". "12".

11 < 3 // . false.

"11" < "3" // . true.

5.7. 89

"11" < 3 // ; "11" 11. false."one" < 3 // ; "one" NaN. false.

, , + , . , , . :

s = 1 + 2 + " "; // "3 "t = " : " + 1 + 2; // " : 12"

, + , . , :

s = (1 + 2) + " "; // ; t = (" : " + 1) + 2; //

5.7. . if, while for.

5.7.1. (&&) && : true , true. false, false.

. . false ( null, 0, "" undefined), . .1

, , . , &&. , JavaScript :

if (a == b) stop();(a == b) && stop();

( Perl) , . , , . :

1 JavaScript 1.0 1.1, false, && .

90 5.

if ((a == null) && (b++ > 10)) stop();

, , , . . , false. , , (, , ), &&, , .

, . , , , .

5.7.2. (||) || : true, ( ) true. false, false.

|| , , &&, . . true, . .1

&&, , , , .

|| , , . . .

, || , , , , . , || , null (. . , true). :

// max_width , . // preferences. // ( max_with) , // , .var max = max_width || preferences.max_width || 500;

1 JavaScript 1.0 1.1, true, true, .

5.8. 91

5.7.3. (!) ! , . . , a true ( , true), !a false. p && q false ( , false), !(p && q) true. , , : !!x.

5.8. , JavaScript , . 32 , . , , . .

32 , 32 , 32. , 0 31. 32 5, .

, , , . JavaScript. :

(&)

& . 1, 1 . 0x1234 & 0x00FF 0x0034.

(|)

| . 1, 1 . , 9 | 10 11.

(^)

^ . , , , . , ( ) . , 9 ^ 10 3.

92 5.

(~)

~ , . . JavaScript ~ 1., ~0x0f 0xfffffff0, 16.

(> 1 3, 7 >> 1 4.

(>>>)

>>> >> , . , 1 >> 4 1, 1 >>> 4 268435455 (0x0fffffff).

5.9. 4, JavaScript =. :

i = 0

JavaScript , , = .

= , . . . = , , , , .

5.9. 93

= , . , :

(a = b) == 0

, = == !

, . , , :

i = j = k = 0;

, , . ( ) (), ( ) .

5.9.1. (=) JavaScript , . , += . :

total += sales_tax

total = total + sales_tax

, += , . , , .

=, *=, &= . . 5.2.

5.2.

+= a += b a = a + b

= a = b a = a b

*= a *= b a = a * b

/= a /= b a = a / b

%= a %= b a = a % b

> b

>>>= a >>>= b a = a >>> b

&= a &= b a = a & b

|= a |= b a = a | b

^= a ^= b a = a ^ b

94 5.

( op ):

a op= ba = a op b

, a , , .

5.10. JavaScript , .

5.10.1. (?:) ( ) JavaScript . ?:, . , ?, ? :, :. :

x > 0 ? x*y : x*y

( ) . . , , . true, . false, .

if, ?: . , , , , , , :

greeting = "hello " + (username != null ? username : "there");

if, :

greeting = "hello ";if (username != null) greeting += username;else greeting += "there";

5.10.2. typeof typeof , . , .

typeof "number", "string" "boolean", , .

5.10. 95

, ( ) null "object". "function", "undefined".

typeof "object", Number, String Boolean. "object" Date RegExp. , JavaScript, , JavaScript, typeof . JavaScript typeof "object" , .

typeof , , :

typeof i(typeof value == "string") ? "'" + value + "'" : value

typeof , typeof , :

typeof(i)

typeof "object", , . , , instanceof constructor ( Object.constructor, ).

typeof ECMAScript v1 JavaScript 1.1 .

5.10.3. (new) new . , :

new ()

, , , . new JavaScript , , . new:

o = new Object; // d = new Date(); // Date, c = new Rectangle(3.0, 4.0, 1.5, 2.75); // Rectangleobj[i] = new constructors[i]();

new , , , this.

96 5.

. 7 new, this .

new new Array(). 7.

5.10.4. delete delete , , .1 true, , false . JavaScript . , , var. delete , true. ( , ECMAScript , delete true, , .) :

var o = {x:1, y:2}; // ; delete o.x; // ; truetypeof o.x; // ; "undefined"delete o.x; // ; truedelete o; // ; falsedelete 1; // ; truex = 1; // vardelete x; // ; truex; // : x

: , undefined. , . 4.3.2.

, delete , , . :

var my = new Object(); // "my"my.hire = new Date(); // my.hire Datemy.fire = my.hire; // my.fire delete my.hire; // hire ; truedocument.write(my.fire); // my.fire Date

5.10.5. void void , . :

1 , C++, , delete JavaScript delete C++. JavaScript . delete C++, , .

5.10. 97

undefined. URL javascript:, , .

, void HTML:

void undefined. void ECMAScript v1 JavaScript 1.1. ECMAScript v3 undefined, JavaScript 1.5. void 0, undefined.

5.10.6. (,) . , , . .

i=0, j=1, k=2;

2 :

i = 0;j = 1;k = 2;

; , , . for, 6.

5.10.7. 3, ([]), (.). , JavaScript .

, ( ). , ; . :

document.lastModifiednavigator.appNameframes[0].lengthdocument.write("hello world")

, JavaScript , undefined.

, .

98 5.

: . .

[] . , . ( ) , ( ) , . :

frames[1]document.forms[i + j]document.forms[i].elements[j++]

[] , , , . : , . , , , . :

document["lastModified"]frames[0]['length']data["val" + i]

[] . , , . . . , , []. for/in, 6. , o for/in []:

for (f in o) { document.write('o.' + f + ' = ' + o[f]); document.write('');}

5.10.8. () JavaScript . , . , . , , . . () , , . :

document.close()Math.sin(x)alert("Welcome " + name)Date.UTC(2000, 11, 31, 23, 59, 59)funcs[i].f(funcs[i].args[0], funcs[i].args[1])

, JavaScript, . , . , ' JavaScript, . JavaScript. JavaScript , , .

JavaScript, , 2.4 , JavaScript . , JavaScript . .

6.1. JavaScript , . 5. . :

s = " " + name;i *= 3;

, ++ , . , :

counter++;

delete . , :

100 6.

delete o.x;

. :

alert(" , " + name);window.close();

, , .

, , . , :

Math.cos(x);

, :

cx = Math.cos(x);

: .

6.2. 5 , . JavaScript . . , , JavaScript :

{ x = Math.PI; cx = Math.cos(x); alert("cos(" + x + ") = " + cx);}

, , . , .

, . , JavaScript ( ); . JavaScript , . , .

, JavaScript ,

6.3. if 101

. , . , break, continue, return throw . .

6.3. if if , JavaScript , , . . :

if ()

if . true true, . false false, . :

if (username == null) // username null undefined, username = "John Doe"; //

:

// username null, undefined, 0, "" NaN, // false, .if (!username) username = "John Doe";

, if. , . if :

if ((address == null) || (address == "")) { address = "undefined"; alert(", .");}

, , . JavaScript, , . , , .

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if ()

1else

2

, true, 1, 2. :

102 6.

if (username != null) alert(" " + username + "\n .");else { username = prompt(" !\n ?"); alert(" " + username);}

if else , else if. :

i = j = 1;k = 2;if (i == j) if (j == k) document.write("i k");else document.write("i j"); // !!

if if. , ( , ), if else. , JavaScript :

if (i == j) { if (j == k) document.write("i k"); else document.write("i j"); // OOPS!}

JavaScript ( ): else if. , , , :

if (i == j) { if (j == k) { document.write("i k"); }}else { // ! document.write("i j");}

if else ( , while) , . , .

6.4. else if , if/else

6.5. switch 103

. ? else if. JavaScript, , if/else:

if (n == 1) { // 1}else if (n == 2) { // 2}else if (n == 3) { // 3}else { // else , 4}

. if, if else . else if , :

if (n == 1) { // 1}else { if (n == 2) { // 2 } else { if (n == 3) { // 3 } else { // else , 4 } }}

6.5. switch if . if, . , . if.

switch , if. switch JavaScript switch Java C. switch , if:

104 6.

switch() { }

switch , . case, . switch, , case, . , , , case. case , , default:. default: , .

switch , . switch if/else, :

switch(n) { case 1: // , n == 1 // 1. break; // case 2: // , n == 2 // 2. break; // case 3: // , n == 3 // 3. break; // default: // ... // 4. break; // }

break case. break, , switch . case switch , . break switch case, , , . , case , 99 % case break. ( switch break return. switch case.)

switch; , :

function convert(x) { switch(typeof x) { case 'number': // return x.toString(16); case 'string': // , return '"' + x + '"'; case 'boolean': // TRUE FALSE,

6.6. while 105

return x.toString().toUpperCase();

default: //

return x.toString()

}

}

: case . switch , ECMAScript v3 case .1 :

case 60*60*24:

case Math.PI:

case n+1:

case a[0]:

switch switch, case , , .2 ===, ==, .

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, case switch, switch default:. default: , switch . , default: switch case. , switch.

6.6. while if , JavaScript , while

1 switch JavaScript switch C, C++ Java. case , , integer , .

2 , switch JavaScript , C, C+ Java. case , , , JavaScript. , case C, C++ Java , switch .

106 6.

, JavaScript . :

while ()

while . false, JavaScript , true, , , . , false, JavaScript , . , false, while JavaScript . while(true) .

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var count = 0;while (count < 10) { document.write(count + ""); count++;}

, count 0, , . 10 , false(. . count 10), while JavaScript . , count. i, j k, , .

6.7. do/while do/while while, , , . , . :

do while ();

do/while , while. , , , . :

6.8. for 107

function printArray(a) { if (a.length == 0) document.write(" "); else { var i = 0; do { document.write(a[i] + ""); } while (++i < a.length); }}

do/while while . , do do ( ), while ( ). , while, do . , do , , .

6.8. for, for, , while. for , ( while). . , . , , .

, , ; for . , for, , . for:

for(; ; )

for, while:1

;while() { ;}

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1 continue, while for.

108 6.

JavaScript , var, . , . true, , . . , , . , , ++ .

while , 0 9, for:

for(var count = 0; count < 10; count++)

document.write(count + "");

, , . , for ; .

, , , . JavaScript, , for. :

for(i = 0, j = 10; i < 10; i++, j)

sum += i * j;

6.