Ò׽ؽØÍ¼Èí¼þ¡¢µ¥Îļþ¡¢Ãâ°²×°¡¢´¿ÂÌÉ«¡¢½ö160KB

javascriptµÄdelete

¸Õ¸Õ°Ý¶ÁÁË JavascriptµÄ±äÁ¿Óëdelete²Ù×÷·û ºÜÊÜÆô·¢¡£Ô­ÎÄֻ˵Á˽á¹û£¬Ã»¸üÉîÈëÍÆÀí×ܽáÒ»ÏÂΪʲô£¬ÒÔ¼°ÔõôÀí½âºÃÒ»µã£¬ÎÒÕâÀï²¹³ä×ܽáһϡ£
 /// <reference path="http://tech.idv2.com/2008/01/09/javascript-variables-and-delete-operator/" />
/*
Óëc++²»Í¬£¬javascriptµÄdelete²»»áɾ³ýÊôÐÔËùÖ¸ÏòµÄ¶ÔÏó
“ɾ³ýÊôÐÔ¶ø²»ÊÇɾ³ý¶ÔÏó”ÕâÒ»µã£¬¿ÉÒÔͨ¹ýÒÔϵĴúÂëÀ´È·ÈÏ¡£
*/
var o = {};
var a = { x: 10 };
o.a = a;
delete o.a; // o.aÊôÐÔ±»É¾³ý
o.a; // undefined
a.x; // 10, ÒòΪ{ x: 10 } ¶ÔÏóÒÀÈ»±» a ÒýÓã¬ËùÒÔ²»»á±»»ØÊÕ
/*
ÊôÐÔdelete**½áÂÛ£ºdeleteɾ³ý¶ÔÏóʵÀýµÄÊôÐÔ Ö»¶Ô¶ÔÏóʵÀý²Ù×÷,²»»áÓ°Ïìµ½ËûµÄÀàÐͺÍÔ­ÐÍ
*/
function C() { this.x = 42; } //¹¹Ô캯Êý¡£
C.prototype.x = 12; //¸øoµÄÔ­ÐͶÔÏóÌí¼ÓÊôÐÔx£¬ËùÒÔ²»»á±»delete¡£
var o = new C(), d = new C();
alert(o.prototype); //ÏÔʾundefined£¬ÒòΪÆäʵֻÓк¯Êý²ÅÓÐprototypeÊôÐÔ
//alert(C.prototype.isPrototypeOf(o));
alert(o.x); // 42, ¹¹Ô캯ÊýÖж¨ÒåµÄo.x
delete o.x; // deleteɾ³ýÊôÐÔ Ö»¶Ô¶ÔÏóʵÀý²Ù×÷,²»»áÓ°Ïìµ½ËûµÄÔ­ÐÍ
alert(o.x); // 12 ÔÚ×ÔÉíÉÏÕÒ²»µ½x£¬¾Í»á²éÕÒÔ­ÐÍÁ´¡£
alert(d.x); // 42 ÒòΪֻɾÁËʵÀýoµÄxÊôÐÔ£¬²¢Ã»É¾ÊµÀýdµÄxÊôÐÔ£¬ÕâÀï²»»áÏÔʾundefined
/*
²âÊÔ±äÁ¿delete**½áÂÛ£ºÍ¨¹ývarÉùÃ÷µÄ±äÁ¿ºÍͨ¹ýfunctionÉùÃ÷µÄº¯ÊýÓµÓÐDontDeleteÌØÐÔ£¬
ÎÞ·¨±»É¾³ý¡£Èç¹ûÄãÔø¾­ÓñհüÄ£Äâ¹ýÀàµÄ˽ÓÐÊôÐÔ¡¢·½·¨£¬ÄÇÒ²¿ÉÒÔÕâÑùÀí½â£¬Í¨¹ývarºÍ
functionÉùÃ÷µÄ±äÁ¿ºÍÓÐÃûº¯Êý£¬¶¼ÊÇ¿ÉÒÔ¿´×öÀàµÄ˽ÓеijÉÔ±£¬Ë½ÓгÉÔ±¾ßÓÐDontDeleteÌØÐÔ¡£
*/
var a = 1;
delete a;
b = 2; //ûÓÐÓÃvar£¬¿ÉÒÔÀí½âĬÈÏΪ¹«ÓеÄÊôÐÔ£¬¿ÉÒÔ±»É¾³ý
delete b;
alert(typeof b); //undefinded£¬±»É¾ÁË
function foo() {//È«¾Ö¶ÔÏóµÄ˽Óз½·¨
return 42;
}
delete foo;
alert(foo()); // 42
function foo1() {
var local = 36;
delete local; // ɾ³ýlocal£¬ºÜÏÔÈ»localÊÇ˽ÓгÉÔ±£¬Ã»É¾µô
alert(local);
}
foo1();
/*
evalºÍdelete**½áÂÛ£ºeval±È½ÏÌØÊ⣬²Î¿¼
http://tech.idv2.com/2008/01/09/javascript-variables-and-delete-operator/#content_2_4
*/
eval("var x = 36;"); //×¢Ò⣺evalÊÜ×÷ÓÃÓòÓ°Ï죬¸ü¶à²Î¿¼htt


Ïà¹ØÎĵµ£º

JavaScript ÑÕÉ«ÌݶȺͽ¥±äЧ¹û¸üÐÂ

½üÀ´¿´ÁËDeanµÄ“Convert any colour value to hex in MSIE”£¬ÖÕÓÚ½â¾öÁ˸ù¾Ý¹Ø¼ü×Ö»ñÈ¡ÑÕÉ«rgbÖµµÄÎÊÌâ¡£
˳±ã°Ñ³ÌÐòÒ²ÖØÐÂÕûÀíÒ»·¬£¬²¢Ê¹ÓÃÁË×î½üÕûÀíµÄ¹¤¾ß¿â¡£
Ч¹ûÔ¤ÀÀµ½ÕâÀï
ÏÂÔØÍêÕûʵÀý
³ÌÐò˵Ã÷
¡¾ColorGradsÑÕÉ«Ìݶȡ¿
³ÌÐòColorGradsµÄ×÷ÓÃÊǸù¾ÝÑÕÉ«¼¯ºÏºÍ½¥±ä¼¶ÊýÉú³ÉÑÕÉ«Ìݶȼ¯ºÏ¡£
½¥±ä¼ ......

°´¶ÔÏó·½Ê½µ÷ÓÃjavascriptµÄÀý×Ó

 Ò³Ã棺
<script type="text/javascript" src="js/test.js"></script>
¡£¡£¡£¡£
<body onload="new myTest();" >
ÒÔ¶ÔÏó·½Ê½µ÷ÓÃÐèҪʹÓà new ²Ù×÷·û£¬test.jsµÄÄÚÈÝ:
{                  & ......

javascriptÕýÔò±í´ïʽ

JavaScript--ÕýÔò±í´ïʽ
ÕýÔò±í´ïʽ(regular expression)¶ÔÏó°üº¬Ò»¸öÕýÔò±í´ïʽģʽ(pattern)¡£Ëü¾ßÓÐÓÃÕýÔò±í´ïʽģʽȥƥÅä»ò´úÌæÒ»¸ö´®(string)ÖÐÌØ¶¨×Ö·û(»ò×Ö·û¼¯ºÏ)µÄÊôÐÔ(properties)ºÍ·½·¨(methods)¡£
ÕýÔò±í´ïʽ¹¹Ô캯Êý£º new RegExp("pattern"[,"flags"]);
²ÎÊý˵Ã÷£º
pattern -- Ò»¸öÕýÔò±í´ïʽÎı¾
flag ......

JavaScript ¸´Ñ¡¿òȫѡ£¨¶þ£©

 
Code:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>ÎÞ±êÌâÒ³</title>
<mce:script language="javascript" type="te ......

JavaScript ¸´Ñ¡¿òµÄ·´Ñ¡

 
Code:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>ÎÞ±êÌâÒ³</title>
<mce:script language="javascript" type="te ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØÍ¼ | ¸ÓICP±¸09004571ºÅ