closures - Javascript infamous Loop issue?

I like to write simple explanations for thick people, because I'm thick so here goes ...

We have 5 divs on the page, each with an ID ... div1, div2, div3, div4, div5

jQuery can do this ...

for (var i=1; i<=5; i++) {
    $("#div" + i).click ( function() { alert ($(this).index()) } )
}

But really addressing the problem (and building this up slowly) ...

STEP 1

for (var i=1; i<=5; i++) {
    $("#div" + i).click (
        // TODO: Write function to handle click event
    )
}

STEP 2

for (var i=1; i<=5; i++) {
    $("#div" + i).click (
        function(num) {
            // A functions variable values are set WHEN THE FUNCTION IS CALLED!
            // PLEASE UNDERSTAND THIS AND YOU ARE HOME AND DRY (took me 2 years)!
            // Now the click event is expecting a function as a handler so return it
            return function() { alert (num) }
        }(i) // We call the function here, passing in i
    )
}

SIMPLE TO UNDERSTAND ALTERNATIVE

If you can't get your head around that then this should be easier to understand and has the same effect ...

for (var i=1; i<=5; i++) {
    function clickHandler(num) {
        $("#div" + i).click (
            function() { alert (num) }
        )
    }
    clickHandler(i);
}

This should be simple to understand if you remember that a functions variable values are set when the function is called (but this uses the exact same thought process as before)