Looking in the jQuery core I found the folloiwng code convention:

nth: function(elem, i, match){
    return match[3] - 0 === i;
},

And I was really curious about the snippet match[3] - 0

Hunting around for '-0' on google isn't too productive, and a search for 'minus zero' brings back a reference to a Bob Dylan song.

So, can anyone tell me. Is this some sort of performance trick, or is there a reason for doing this rather than a parseInt or parseFloat?

Thanks