the right way to pass variable to a callback function

Question

When I have

$('#div').click(function(someVar){//do something with soneVar});

but I want to have a named callback function, am I palcing the passed someVar correctly?

$('#div').click(someFunction(someVar));
function someFunction(someVar){}

Solution 1

Both of your examples are wrong.

Your first example creates a parameter to the callback method named someVar; it will become the event object that jQuery passes to the handler method.

The second example calls the method immediately, then passes its result to the click method as an event handler.

You you need to pass a function expression that calls your function with a parameter from the outer scope (using a closure):

$('#div').click(function() { someFunction(someVar); });

Solution 2

The click callback function will be passed a jQuery Event object, not someVar.

You have to call your function yourself within the callback function.

$('#div').click(function(ev) {
    someFunction(someVar);
}

function someFunction(someVar) {
     ...
}

Alternatively, do:

$('#div').click({someVar: someVar}, someFunction);

function someFunction(ev) {
    // your var is now in ev.data.someVar
}