js怎么判断undefined?
网友回复
<script>
var exp = undefined;
if (typeof(exp) == "undefined")
{
alert("undefined");
}
</script>
by thinkfuture
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最新提问
js怎么判断undefined?
网友回复
<script>
var exp = undefined;
if (typeof(exp) == "undefined")
{
alert("undefined");
}
</script>
