Stand-alone, straightforward debounce function. Executes the callback at the end (no option for executing at start).

debounce.js

function debounce( callback, delay, context ) {
    var timer;

    return function () {
        var _this = context || this,
            args = arguments;

        // Clear a timer which has been created earlier in the sequence of calls.
        timer && clearTimeout( timer );

        // (Re-)start the timer, ie create a new one.
        timer = setTimeout( function () {
            callback.apply( _this, args );
        }, delay );
    };
}