Question

I have a function call in my script that contain a callback function call on a fadeOut call. I’m trying to pass the paren’t function parameter into the callback function, but I can’t seem to get it working.

The general script structure is:

function aFunction(aVar){
    anElement.fadeOut(200, function(){
        someFunctionCall(aVar);
    });
}

The call is performed correctly, but the variable is not passed. It’s probably a scoping issue on the variable but I don’t quite understand the concept here.

Answer 1

This code

function aFunction(aVar){
    anElement.fadeOut(200, function(){
        someFunctionCall(aVar);
    });
}

is correct as written. Your inner function, and any other functions you declare, automatically have access to all variables in the containing scope. The function you’re passing to fadeOut will form a closure over aVar, and continue to have access to it even after aFunction has long since returned.