js实现点击按钮控制展开与收起.

html

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title>下拉与收起</title>
		<link rel="stylesheet" href="css/showhide.css" />
		<script type="text/javascript" src="js/showhide.js" ></script>
	</head>
	<body>
		<div id="showhide">
			<p>假如生活欺骗了你</p>
			<p>不要悲伤，不要哭泣</p>
			<p>忧郁的日子总会过去的</p>
			<div id="show" style="display:none;">
				<p>
					因为你要知道，再挣扎也是没用的，它还是会再欺骗你一次
				</p>

				<p>
				直至你在失望与孤独中死去
				</p>
			</div>

		</div>
		 <p class="slide">
            <a href="javascript:showdiv();"  id="strHref"   class="btn-slide">更多选项+
            </a>
		 </p>

	</body>
</html>

　　css

 body
        {
            margin: 0 auto;
            padding: 0;
        }
        a:focus
        {
            outline: none;
        }
        #showhide
        {
            background: black;
            color: white;
            width: 600px;
            display: block;
            margin: 0 auto;
            padding: 5px;
            font-size: 20px;

            height: auto;
            font-family: "微软雅黑";
        }
        .slide
        {
            margin: 0;
            padding: 0;
            width: 600px;
            border-top: solid 4px gray;
            margin: 0 auto;
        }
       .btn-slide
        {
            background: gray;
            text-align: center;
            width: 120px;
            height: 30px;
            padding: 10px 10px 0 0;
            margin: 0 auto;
            display: block;
            color: #fff;
            text-decoration: none;
        }

　　js

   function showdiv()  {
   	document.getElementById("show").style.display = "block";

   	 document.getElementById('strHref').innerHTML="收起";
   	 document.getElementById('strHref').href="javascript:hidediv();";
   }
   function hidediv() {
   	  document.getElementById('show').style.display='none';
   	 document.getElementById('strHref').innerHTML="更多选项+";
   	 document.getElementById('strHref').href="javascript:showdiv();";
   }

　　效果；