能否在某个网页元素后面增加东西?
<div>  
  <div   id= "id123 "> 456 </div>  
  <div   id= "id789 "> abc </div>  
 ...... 
 ...... 
 ...... 
  <div>    
 能否在id123的后面(而不是后部)增加文本或者HTML元素?变成   
  <div>  
  <div   id= "id123 "> 456 </div> 这里是我添加的文本 <span> 这里是我添加的元素 </span>  
  <div   id= "id789 "> abc </div>  
 ...... 
 ...... 
 ...... 
  <div>  
------解决方案--------------------这样行不?   
  <html>  
  <head>  
  <meta http-equiv= "Content-Type " content= "text/html; charset=gb2312 ">  
  <title> new page </title>  
  <script>  
 function a(){ 
 var oDiv=document.getElementById( "id123 "); 
 oDiv.outerHTML=oDiv.outerHTML+ "这里是我添加的文本 <span> 这里是我添加的元素 </span>  "; 
 alert(document.body.innerHTML); 
 } 
  </script>  
  </head>  
  <body onload= "a() ">  
  <div>  
  <div id= "id123 "> 456 </div>  
  <div id= "id789 "> abc </div>  
  </div>  
  </body>  
  </html>
------解决方案--------------------可以:   
  <script type= "text/javascript ">  
 	function insd(){ 
 		var mydiv=document.getElementById( "id123 "); 
 			myspan=document.createElement( "span "); 
 			myspan.innerHTML= "这里是我添加的元素 "; 
 			mydiv.parentNode.insertBefore(myspan,mydiv.nextSibling); 
 	}  	 
  </script>  
  <div id= "id123 "> 456 </div>  <div id= "id789 "> abc </div>  
 ...... 
 ...... 
 ...... 
  </div>  
  <input type= "button " value= "插入 " onclick= "insd() " />
------解决方案-------------------- <script language= "javascript " type= "text/javascript ">  
 function $() 
 { 
   var arr=new Array() 
   var divs=document.getElementById( "hjx ").getElementsByTagName( "div "); 
   for(var i=0;i <divs.length;i++) 
   { 
     arr[i]=divs[i]; 
   } 
   for(var i in arr) 
   { 
   document.getElementById( "hjx ").appendChild(arr[i]); 
   var sp=document.createElement( "span "); 
   sp.innerHTML= "这里是我添加的元素 "; 
   document.getElementById( "hjx ").appendChild(sp); 
   } 
 } 
  </script>  
  <input type= "button " value= "测试 " onclick= "$() " />  
  <div id= "hjx ">  
  <div id= "id123 "> 456 </div>  
  <div id= "id789 "> abc </div>  
  <div id= "id123 "> 456 </div>  
  <div id= "id789 "> abc </div>  
  <div>  
------解决方案-------------------- <script language= "javascript " type= "text/javascript ">  
 function $() 
 {     
   var arr=new Array() 
   var divs=document.getElementById( "hjx ").getElementsByTagName( "div "); 
   for(var i=0;i <divs.length;i++) 
   { 
     arr[i]=divs[i]; 
   } 
   for(var i=0;i <arr.length-1;i++) 
   { 
   document.getElementById( "hjx ").appendChild(arr[i]); 
   var sp=document.createElement( "span "); 
   sp.innerHTML= "这里是我添加的元素 ";