判断是否为undefined
var example = undefined;if (typeof(example) == "undefined"){console.log("undefined")}
判断是否为null
var example = null; if (!example && typeof(example)!='undefined' && example!=0) {console.log("null");}
时间:2021-08-19 03:13:08
var example = undefined;if (typeof(example) == "undefined"){console.log("undefined")}
var example = null; if (!example && typeof(example)!='undefined' && example!=0) {console.log("null");}
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