js判断 ,,null,undefined?script typetext/javascript//判断js ,,null,undefinedfunction te
js判断 '',"",null,undefined
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<script type="text/javascript">//判断js '',"",null,undefinedfunction test(a){if(a){alert("");}else{ alert("else");}}test(); //输出: elsetest('');//输出:ielsetest("");//输出:elsetest(null);//输出:else</SCRIPT>?
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