How to get object length [duplicate]
For browsers supporting Object.keys() you can simply do:
Object.keys(a).length;Otherwise (notably in IE < 9), you can loop through the object yourself with a for (x in y) loop:
var count = 0;var i;for (i in a) { if (a.hasOwnProperty(i)) { count++; }}The hasOwnProperty is there to make sure that you're only counting properties from the object literal, and not properties it "inherits" from its prototype.
This should do it:
Object.keys(a).lengthHowever, Object.keys is not supported in IE8 and below, Opera and FF 3.6 and below.
Live demo: http://jsfiddle.net/simevidas/nN84h/