案例：javascript案例     状态：可编辑再运行    进入竖版
 运行结果　
​x
 
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<html>
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<head>
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<base id="myBaseId" target="_blank"
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href="//www.w3xue.com/" />
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</head>
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​
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<body>
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​
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<p>Base target:
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<script type="text/javascript">
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x=document.getElementById('myBaseId');
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document.write(x.target);
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</script>
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​
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</body>
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</html>