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

Javascript±äÁ¿×÷ÓÃÓò

ÇëÏÈ¿´ÏÂÌ⣺
if(true)
{
     a = 1;
}
alert(a);  //Êä³öɶ£¿
if(true)
{
    var a = 1; 
}
alert(a);  //ÕâÓÖÊä³öʲô£¿
ÔÚfirefox3.5Ï£¬µÚÒ»¸öÊä³ö1;µÚ¶þ¸öÊä³öundefined£¡£¡£¡
ÎªÉ¶ÄØ£¿ºÇºÇ£¬±¾ÈËÔڴ˰àÃÅŪ¸«Ò»Ï£º
Ò»°ãÇé¿öÏÂȱʡvarÉùÃ÷ʱ£¬Ä¬ÈϸñäÁ¿ÎªÈ«¾Ö±äÁ¿¡£Á˽âÕâ¾ä»°£¬ËùÓÐÎÊÌâÒ²¾ÍÓ­Èжø½âÁË£¡ºÇºÇ£¡
µÚÒ»µÀÌ⣺±äÁ¿aȱʡvarÉùÃ÷£¬¶øÖ±½ÓʹÓ㬹ʶøÄ¬ÈÏΪȫ¾Ö±äÁ¿£¬Êä³ö1
µÚ¶þµÀÌ⣺±äÁ¿a£¬ÔÚif¿éÖÐvarÉùÃ÷£¬Êô¾Ö²¿±äÁ¿£¬Êä³öundefined£¡


Ïà¹ØÎĵµ£º

JavaScript ¹¹Ô캯Êý myhere

/**
* JavaScript ÊÇÃæÏò¶ÔÏóµÄÓïÑÔ£¬µ«ÊÇËûµÄÃæÏò¶ÔÏó²»ÊÇ»ùÓÚÀàµÄ£¬ÊÇ»ùÓÚÔ­Ð͵Ä;
* µ«ÊÇËûµÄÒ»Ð©ÌØÐÔ(º¯ÊýÊÇÊý¾Ý)£¬Ê¹µÃËü¿ÉÒÔÄ£Äâ»ùÓÚÀàµÄÃæÏò¶ÔÏ󣬵«ÊÇ JavaScript ²¢²»Ö§³ÖºÍ Java Ò»ÑùµÄÀ࣬
* Òò´Ë JavaScript ÖеÄ"Àà"¿ÉÒÔ³Æ×÷"αÀà"
*/
//
/**
* ¹¹Ô캯Êý: js ÖÐÓÃÀ´ºÍ new ÔËËã·ûÒ»ÆðʹÓõĺ¯Êý³Æ× ......

javascript³£ÓÃ

calcu()  ----º¯ÊýʵÏÖÁ½¸öÊýÏà³Ë
document.write();  ---´òÓ¡
document.calc.ÔªËØÃû.value;  --»ñµÃ±íµ¥µÄÖµ
document.±íµ¥Ãû¡£±íµ¥ÔªËØÃû¡£value  Ϊ±íµ¥¸³Öµ
¶¨Ò庯Êý£º
 function  Ãû×Ö()
 {
    //javaScriptÔ¤Óï¾ä
 }
 onClick="º¯ÊýÃû";  ......

[·­Òë]High Performance JavaScript(003)

Dynamic Script Elements  ¶¯Ì¬½Å±¾ÔªËØ
    The Document Object Model (DOM) allows you to dynamically create almost any part of an HTML document using JavaScript. At its root, the <script> element isn't any different than any other element on a page: references can be retrie ......

[·­Òë]High Performance JavaScript(005)

µÚ¶þÕ  Data Access  Êý¾Ý·ÃÎÊ
    One of the classic computer science problems is determining where data should be stored for optimal reading and writing. Where data is stored is related to how quickly it can be retrieved during code execution. This problem in JavaScri ......

һЩjavascriptÌâÄ¿

ȺÀïÌÖÂÛ¹ýµÄÌâÄ¿£¬·ÖÏíһϡ£
function test(){
var m=n=1;
alert(m);
}
alert(n);
//ÒòΪtestº¯ÊýûÓÐÖ´ÐУ¬³Ì¶È¿ØÖÆÁ÷²»ÄܽøÈë½øÐнâÎö£¬ÀïÃæµÄ¶«Î÷¶ÔÍâÃæ²»¿É¼û£¬Òò´Ë±¨´í
function test(){
var m=n=1;
alert(m);
}
test();
alert(n);
//µ±testÖ´Ðкó£¬Í ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØÍ¼ | ¸ÓICP±¸09004571ºÅ