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<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<script src="file:///E|/课程视频/0103Jquery/Jquery/jquery-1.11.2.min.js"></script>
<style type="text/css">
#zz{width:100%; height:100%; position:absolute; left:0px; top:0px; background-color:black; z-index:5;filter:alpha(opacity=50);
-moz-opacity:0.5;
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opacity: 0.5;}
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</head>
<body>
<div >
<input type="button" value="关灯" />
<input type="button" value="开灯" />
</div>
</body>
<script type="text/javascript">
$("#guan").click(function(){
var str = "<div ></div>";
$("body").append(str);
$(this).css("display","none");
$("#kai").css("display","block");
})
$("#kai").click(function(){
$("#zz").remove();
$("#guan").css("display","block");
$(this).css("display","none");
})
</script>
</html>