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<html lang="en">
<head><meta charset="UTF-8"><title>jq之demo</title><!--线上jq库--><script src="https://code.jquery.com/jquery-3.4.1.min.js"></script><script>$(document).ready(function(){$("button").click(function(){/*function()为回调函数在slow执行完后执行*/$("p").hide("slow",function(){alert("段落隐藏");});});});</script>
</head>
<body><button>隐藏</button><br/><p>段落</p>
</body>
</html>