JavaScript: Retrieve key names from an object?

Question

Say I have this:

var x = {  
          a:{a1:"z", a2:"x"},
          b:{b1:"y", b2:"w"}
}

Is there a way to iterate over x to get "a" and "b"?

I want the member name, not its content (I don't want to get {a1:"z", a2:"x"}).

Thanks

Jacob Relkin · Accepted Answer · 2010-09-21 20:26:20Z

27

var names = [];
for(var key in x) {
   if(x.hasOwnProperty(key)) {
      names.push(key);
   }
}
alert(names.join(', ')); //a, b

answered Sep 21, 2010 at 20:26

Jacob Relkin

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1 Comment

Guys, sorry about the undefined k typo. I meant key. :)