如何用JS读出指定ID的DIV里抽值
<div   id= "a "> 111 </div>  
  <div   id= "b "> 222 </div>  
  <div   id= "c "> 333 </div>    
 我现在只想读出222的值,因为这个DIV的位置不确定,所以不能用. 
 alert(document.body.getElementsByTagName( "div ")[0].innerHTML)     
------解决方案--------------------document.getELementById( "b ").innerHTML
------解决方案--------------------document.getElementById( "b ").innerHTML
------解决方案--------------------直接b.innerHTML就好了......
------解决方案-------------------- <div id= "a "> 111 </div>  
  <div id= "b "> 222 </div>  
  <div id= "c ">  <span> 333 <span>  </div>  
  <input type= "button " value= "获取text的值 " onclick= "alert(document.getElementById( 'c ').innerText); " />  
  <input type= "button " value= "获取Html的值 " onclick= "alert(document.getElementById( 'c ').innerHTML); " />
------解决方案--------------------document.getElementById( "b ").innerHTML
------解决方案--------------------document.getElementById( "b ").innerHTML