ife-2016/18.html at master · Kido-200/ife-2016 · GitHub

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<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>task 18</title>
		<style type="text/css">
			ul{
				padding-left:0;
			}
			li{
				display: inline-block;
				 width: 50px;
				 height: 50px;
				 line-height: 50px;
				 text-align: center;
				 background-color: red;
				 color: #fff;
			}
			li:hover{
				cursor:pointer;
			}
		</style>
	</head>
	<body>
		<input type="text">
		<button type="button">左侧入</button>
		<button type="button">右侧入</button>
		<button type="button">左侧出</button>
		<button type="button">右侧出</button>
		<ul></ul>
		<script type="text/javascript">
			var input = document.getElementsByTagName("input")[0];
			var button = document.getElementsByTagName("button");
			var ul = document.getElementsByTagName("ul")[0];
			input.addEventListener("blur",function(){
				if(!input.value.match(/^\d+$/))
				{
					alert("请输入数字");
					input.value="";
				}
			},false);
			//左进
			button[0].addEventListener("click",function(){
				if(input.value=="") return false;
				var li = document.createElement("li");
				var textNode = document.createTextNode(input.value);
				li.appendChild(textNode);
				ul.insertBefore(li,ul.children[0]);//即使ul里面没children[0]也能插进去，牛逼
			},false);
			//右进
			button[1].addEventListener("click",function(){
				if(input.value=="") return false;
				var li = document.createElement("li");
				var textNode = document.createTextNode(input.value);
				li.appendChild(textNode);
				ul.appendChild(li);//即使ul里面没children[0]也能插进去，牛逼
			},false);
			//左退
			button[2].addEventListener("click",function(){
				alert("删除最左侧节点：" + ul.children[0].innerHTML);
				ul.removeChild(ul.children[0]);
			},false);
			//右退
			button[3].addEventListener("click",function(){
				alert("删除最右侧节点：" +ul.children[ul.children.length - 1].innerHTML);
				ul.removeChild(ul.children[ul.children.length - 1]);
			},false);
			//给所有li添加上点击就删除的事件， 很常见的给他们的父亲加个冒泡事件就完事儿了
			ul.addEventListener("click",function(e){
				var event = e||window.event;
				var target = event.target||event.srcElement;
				ul.removeChild(target);
			},false);
		</script>
	</body>

</html>