代码编辑器：
x
1
2
<meta charset="utf-8">3
<link href="/static/next/css/tryit.css?v=2017082407" rel="stylesheet"/>4
<script src="https://cdn.staticfile.org/jquery/2.2.4/jquery.min.js"></script>5
<script>6
$(document).ready(function(){7
$("button").click(function(){8
$("p").toggleClass("main");9
});10
});11
</script>12
<style>13
.main{14
font-size:120%;15
color:red;16
}17
</style>18
<button>转换P元素的"main"类</button>