Question

for example,

var name = [1,2,3]  // name === "1,2,3"
name = {"a":"b"}  // name === "[object Object]"

I don’t understand this situation.

what is the identity of ‘name’ or ‘window.name’ on javascript?

ADD:

I used Chrome’s Dev Tools

Answer 1

When you declare

name = {"a":"b"}

you are creating an object and the string representation of an object is [object Object], that is, when you try to convert an object to a string (which is probably the case here) you get that result.

Note that name === "[object Object]" is not true.

alert( name === "[object Object]" );             // alerts "false"
alert( name.toString() === "[object Object]" );  // alerts "true"

The same holds true for the array. 1,2,3 is just a string representation of array [1,2,3].

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As for window.name, it has the name of the current window so changing it to a non-string might lead to unexpected behavior: https://developer.mozilla.org/en/DOM/window.name