构建自己的JavaScript库：
创建一个IC.js文件
（function（））{
function $(){
alert();
}
window['IC']={}
window['IC']['$']=$;
})();
第二种，加入自己的方法：
(function(){
window['IC']={}
function $(){
var elements = new Array();
for(var i=0;i<arguments.length;i++){
var element = arguments[i];
if(typeof element == 'string'){
element = document.getElementById(element);
}
if(arguments.length==1){
return element;
}
elements.push(element);
}
return elements;
}
window['IC']['$']=$;
function getElementsByClassName(className,tag){
var allTags = document.getElementsByTagName(tag);
var matchingElements = new Array();
className = className.replace(/\-/g, "\\-");
var regex = new RegExp("(^|\\s)" + className + "(\\s|$)");
var element;
for(var i=0; i<allTags.length; i++){
element = allTags[i];
if(regex.test(element.className)){
matchingElements.push(element);
}
}
return matchingElements;
}
window['IC']['getElementsByClassName']=getElementsByClassName;
})();
创建html页面，ICtest.html
<!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>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
<script type="text/javascript" src="IC.js" ></script>
<script type="text/javascript" >
function testClick(){
var testInput = IC.getElementsByClassName("testme","input");
for(var i=0;i<testInput.length;i++){
alert(testInput[i].value);
}
}
</script>
</head>
<body >
<input type="text" value="test" class="testme" id="testId"/>
<input type="text" value="test3" class="testme" id="testId2"/>
<input type="button" value="clickme" onclick="testClick()"/>
</body>
</html>