Question

Possible Duplicate:
How do you determine equality for two JavaScript objects?

Why does [1,[2,3]] == [1,[2,3]] evaluate to false?

Also, why does this happen:

var g = { a:1, b:2, c:3 };
g == { a:1, b:2, c:3 }; // false!! 

Answer 1

[] is a shortcut to make an array literal instead of calling new Array() and then populating it. It’s a similar story for {}. In your example, you are actually comparing by reference instead of by value. Two objects constructed with the new operator point to different locations in memory, and when you use the == operator you are actually saying “do these objects point to the same location in memory?”. To do a by-value comparison like you’re expecting, you would need to iterate through the members of each array/object you’re comparing and compare each value one-by-one.