锘??xml version="1.0" encoding="utf-8" standalone="yes"?>
]]>
鍜?/SPAN>java,c++涓笉鍚岀殑鍦版柟鏄紝js涓病鏈夊潡浣滅敤鍩?/SPAN>(Block Scope)銆傚彉閲忕殑浣滅敤鍩熷皢浠庡0鏄庝竴鐩存寔緇埌function鐨勭粨灝俱傜湅涓緥瀛愬氨浼氭槑鐧戒簡銆?/SPAN>
function testScope()
{
var a = "a";
function g() { alert(a); }
g(); //榪欓噷杈撳嚭緇撴灉涓?/SPAN>a 錛屽洜涓?/SPAN>a鐨勪綔鐢ㄥ煙灝嗘寔緇埌function testScope鐨勭粨灝?/SPAN>
for(var i=0; i<2; i++)
{
var a = "a is changed"; //榪欓噷鐨勫彉閲?/SPAN>a灝嗚鐩栧紑濮嬪0鏄庣殑鍙橀噺a
var b = "b"; //b鐨勪綔鐢ㄥ煙浠庡0鏄庝竴鐩村埌function鐨勭粨灝?/SPAN>
}
alert(a); // 杈撳嚭緇撴灉涓?/SPAN> a is changed錛?/SPAN> js棣栧厛鏌ユ壘鍒扮殑a鏄湪寰幆涓畾涔夌殑閭d釜
alert(b); // 杈撳嚭涓?/SPAN> b 鍦?/SPAN>java涓?/SPAN>,姝ゆ椂灝嗚闂笉鍒板彉閲?/SPAN>b,b宸茬粡鍑轟簡浣滅敤鍩?/SPAN>,浣嗘槸鍦?/SPAN>js涓槸鍙互鐨?/SPAN>.
}
2. js涓殑鍨冨溇鍥炴敹錛?/SPAN>garbage collection錛?/SPAN>
js涔熸槸涓闂ㄩ噰鐢ㄥ瀮鍦懼洖鏀舵満鍒剁殑璇█錛屽拰java涓鏍楓?/SPAN>js鐨勮В閲婂櫒璐熻矗鍒嗛厤鍜屽洖鏀跺唴瀛樸?/SPAN>
紼嬪簭鍛樻棤闇鍍?/SPAN>C錛嬶紜涓偅鏍鋒墜鍔ㄧ敤delete閲婃斁鍐呭瓨銆?/SPAN>
浣嗘槸js涔熸湁delete鍏抽敭瀛?/SPAN>錛?STRONG>瀹冩槸鐢ㄦ潵鍒犻櫎瀵硅薄鐨勫睘鎬э紝鎴栬呭垹闄ゆ暟緇勪腑鐨勬寚瀹氬厓绱?/STRONG>銆傚茍涓嶈兘鍒犻櫎瀵硅薄鏈韓銆傜敤娉曞涓嬶細
delete objectName.property
delete objectName[index]
delete property
鍙傛暟
property |
|
絎笁縐嶇敤娉昫elete property鍙兘鍦?/SPAN> with 璇彞涓嬌鐢紝鐢ㄦ潵鍒犻櫎瀵硅薄鐨勫睘鎬с?BR>
琛ュ厖錛氬湪寰蔣鐨凧Script涓湁CollectGarbage()鍑芥暟鍙互鐢ㄦ潵鍥炴敹鍐呭瓨錛屽畼鏂規枃妗d笉鎺ㄨ崘浣跨敤姝ゆ柟娉曪紝浣犵殑紼嬪簭涓嶅簲璇ヤ緷璧栨鏂規硶銆侷E鍦ㄦ渶灝忓寲鐨勬椂鍊欎細榪涜鍥炴敹鍐呭瓨銆?BR>