js获取封装对象/通过id tag className

 1 <script language="javascript" type="text/javascript">
 2 /*-------------封装开始------------------*/
 3 function GetId(id){return document.getElementById(id)}  //通过ID获取对象
 4 function GetTag(tag){return document.getElementsByTagName(tag)}  //通过Tag获取对象
 5 function GetChildTag(id,tag){return id.getElementsByTagName(tag)}  //通过Tag获取ID的子对象
 6 function GetClass(className){return getElementsByClassName(className)}  //通过className获取对象
 7 var $c=function(array){var nArray = [];for (var i=0;i<array.length;i++) nArray.push(array[i]);return nArray;};
 8     Array.prototype.each=function(func){for(var i=0,l=this.length;i<l;i++) {func(this[i],i);};};
 9 var getElementsByClassName=function(cn){
10         var hasClass=function(w,Name){
11         var hasClass = false;
12         w.className.split(' ').each(function(s){
13             if (s == Name) hasClass = true;
14         });
15         return hasClass;
16             };
17         var elems =document.getElementsByTagName("*")||document.all;
18             var elemList = [];
19            $c(elems).each(function(e){
20                if(hasClass(e,cn)){elemList.push(e);}
21            })
22             return $c(elemList);
23     };        
24 /*-----------------封装结束---------------------*/
25 window.onload=function(){
26      GetTag("input")[0].onclick=function(){alert("id为test的div内容是：\n"+GetId("test").innerHTML)}
27                  GetTag("input")[1].onclick=function(){alert("body里共有"+GetTag("li").length+"个li")}    
28                  GetTag("input")[2].onclick=function(){alert("DIV里共有"+GetChildTag(GetId("test"),"li").length+"个li")}
29                  GetTag("input")[3].onclick=function(){alert("className为test2的内容是：\n"+GetClass("test2")[0].innerHTML+"\n"+GetClass("test2")[1].innerHTML)}
30     }
31 </script>

 1 <div id="test" title="这是id=test的div">
 2     <ul title="div内第一个ul">
 3       <li>ccontent1</li>
 4       <li>ccontent2</li>
 5       <li>ccontent3</li>
 6       <li>ccontent4</li>
 7     </ul>
 8     <ul class="test2" title="div内第二个ul，class=test2">
 9        <li>bcontent1</li>
10        <li>bcontent2</li>
11        <li>bcontent3</li>
12     </ul>
13 </div>
14 <ul class="test2" title="div外的ul，class=test2">
15   <li>content1</li>
16   <li>content2</li>
17 </ul>
18 <input type="button" value="通过id获取" />
19 <input type="button" value="通过tag获取" />
20 <input type="button" value="通过id内tag获取" />
21 <input type="button" value="通过className获取" />