<script type="text/javascript" language="javascript">

 function newNode(thisid,thisname) {  
    //得到当前出入的个数
    var thislength=document.getElementById(thisid).getElementsByTagName(‘li‘).length;
 
    if(thislength<=5){//最多有6个input
 
     var olElement = document.getElementById(thisid);  
     var liElement = document.createElement(‘li‘);  
    
     var inputElement = document.createElement(‘input‘);  
     inputElement.type = "text";  
     inputElement.name = thisname;  
    
     liElement.appendChild(inputElement);  
     olElement.appendChild(liElement);  
     
    }
   }
   
</script>

html部分代码
<ul id="qqs"><li><input type="text" name="qq[]" ></li></ul>    <span style="color:#0F0; cursor:pointer; font-size:20px; font-weight:bold" onclick="javascript:newNode(‘qqs‘,‘qq[]‘)"  onmouseover="this.style.color=‘#0000FF‘" onmouseout="this.style.color=‘#00FF00‘">⊕</span>