Question

Is there any performance / memory hit differential among the three following styles?

Exhibit A:

var func = function() {
    // do some magic
}

$("#div").somePlugin({someEvent: func});

Exhibit B:

$("#div").somePlugin({someEvent: function() {
    // do some magic
});

Exhibit C:

function func() {
    // do some magic
}

$("#div").somePlugin({someEvent: func});

Answer 1

There might be a little, slightly (really slightly) better performance for the function expression:

var func = function(){
};

That is a such called function expression. The otherside, the function statement is your third example:

function func(){
}

Function statements are converted internally into function expressions by ECMA-/Javascript, so thats the reason why it might(!) be slighty faster, but really, nothing to worry about.

Your B: example shows an anonymous function, which also has no performance impact over the A and C.