变量未定义时,
其被赋为undefined
let aaa; console.log("undefined ...",undefined); console.log("aaa ...", aaa); if(aaa==undefined){ console.log("aaa == undefined" ); } if(aaa===undefined){ console.log("aaa === undefined") }
posted on 2021-07-21 11:25 zhishiyv 阅读(107) 评论(0) 编辑 收藏 举报
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