js操作dom的代码
<script type="text/javascript">
var count=;
function play(){
alert(count);
if(count==){
var btn=document.createElement("input");
btn.setAttribute("id","testinput");
var div=document.getElementById("first");
div.appendChild(btn);
count++;
}else{
var input=document.getElementById("testinput");
var div=document.getElementById("first");
div.removeChild(input);
count--;
}
}
</script>
操作的 结果:

点击创建按钮,再点击删除按钮