一个 javascript 的小问题

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简单来说就是我创建了一个 String.prototype 的方法。只有 return this

结果从 string 变成了 object 这是为啥呢？

更详细的内容我贴在 StackOverflow 了。

那边看起来更方便

http://stackoverflow.com/questions/12020463/javascript-string-object-v-s-just-string

Thanks!

string

return

prototype

2 replies • 1970-01-01 08:00:00 +08:00

dreampuf

Aug 19, 2012

转一个，stackoverflow已经有人回答你了。
http://stackoverflow.com/questions/5146591/javascript-wtf-a-string-prototypes-this-doesnt-return-a-string
The following steps are performed when control enters the execution context for function code contained in function object F, a caller provided thisValue, and a caller provided argumentsList:

If the function code is strict code, set the ThisBinding to thisValue.
Else if thisValue is null or undefined, set the ThisBinding to the global object.
Else if Type(thisValue) is not Object, set the ThisBinding to ToObject(thisValue).
Else set the ThisBinding to thisValue

bitsmix

Aug 19, 2012

@dreampuf thx, 我后来也发现这个是一个重复的问题了。之前脑子卡壳了。