Javascript Best Practices
1. ×ÜÊÇʹÓà ‘var’
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²»Ê¹Óà Var Ôì³ÉµÄÎÊÌâ
var i=0; // This is good - creates a global variable
function test() {
for (i=0; i<10; i++) {
alert("Hello World!");
}
}
test();
alert(i); // The global variable i is now 10!
ÒòΪ±äÁ¿º¯ÊýÖбäÁ¿ i ²¢Ã»ÓÐʹÓà var ʹÆä³ÉΪº¯Êý¼¶µÄ±äÁ¿£¬ÔÚÕâ¸öÀý×ÓÖÐËüÒýÓÃÁËÈ«¾Ö±äÁ¿¡£×ÜÊÇʹÓà var À´ÉùÃ÷È«¾Ö±äÁ¿ÊÇÒ»¸öºÜ¶àµÄ×ö·¨£¬µ«ÖÁ¹ØÖØÒªµÄÒ»µãÊÇʹÓà var ¶¨ÒåÒ»¸öº¯Êý·¶Î§µÄ±äÁ¿¡£ÏÂÃæÕâÁ½¸ö·½·¨ÔÚ¹¦ÄÜÉÏÊÇÏàͬµÄ£º
ÕýÈ·µÄº¯Êý
function test() {
var i=0;
for (i=0; i<10; i++) {
alert("Hello World!");
}
}
ÕýÈ·µÄº¯Êý
function test() {
for (var
i=0; i<10; i++) {
alert("Hello World!");
}
}
2. ÌØÐÔ¼ì²â¶ø·Çä¯ÀÀÆ÷¼ì²â
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if (document.getElementById) {
var element = document.getElementById('MyId');
}
else {
alert('Your browser lacks the capabilities required to run this script!');
}
3. ʹÓ÷½À¨ºÅ¼Ç·¨
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MyObject.property
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MyObject["property"]
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Ö÷Òªº¯Êý CallJScript
BOOL CallJScript(const wchar_t * func, VARIANT * vtParams, int cNumberOfParam, VARIANT * vtResult)
{
if(!func || !func[0])
return FALSE;
CComPtr<IDispatch> spScript;
spScript = GetJScript();
if(!spScript)
return FALSE;
DISPID dispID = NULL;
CC ......
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<script type="text/javascript">
function myInfo(){
var name ="ÀÏÓã",age =27;
var myInfo = "my name is" + name + "i am" + age  ......
<html>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Power Table</title>
<style>
body{
FONT-SIZE: 9pt; PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; PADDING-TOP: 0px;
}
input {
FONT-SIZE: 9pt; height: 15pt; width:50px; ......
Javascript
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if(document.mylist.length != "undefined" ) {} Õâ¸öÓ÷¨ÓÐÎó.
ÕýÈ·µÄÊÇ if( typeof(document.mylist.length) != "undefined" ) {}
»ò if( !isNaN(document.mylist.length) ) {}
typeofµÄÔËËãÊý䶨Òå,·µ»ØµÄ¾ÍÊÇ "u ......