jsuwp-2-11 undefined
2-11 Undefined
千萬不要自己將變數的值設成undefined,以保證undefined都是js engine 所設的,方便debug
作者覺得叫notset 比較合適 😤
1 | console.log(a); |
- a does not exist in memory
1 | var a; |
- a exists in memory, but is set to a special value - undefined
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1 | console.log(a); |
1 | var a; |
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