IE中在input中回车相当于提交form，会从dom中找最近的button标签触发click事件
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
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<h1>by 司徒正美</h1>
<p><input class="text" placeholder='在input框里面按回车键，触发了button的click事件'/></p>
<p>
<button onclick="alert(111)">111</button>
</p>
<button onclick="alert(222)">222</button>
</body>
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