Debounce limits the rate at which a function can fire.

debounce.js

// Debounce limits the rate at which a function can fire.
// Debouncing ensures that exactly one signal is sent for an event that may be happening several times
// See e.g: http://unscriptable.com/2009/03/20/debouncing-javascript-methods/
//          http://davidwalsh.name/javascript-debounce-function

function debounce(fn, treshold, options) {
    'use strict';

    treshold || (treshold = 250);
    options  || (options = {});

    var timeout;

    return function() {
        var context = options.scope || this, 
            args    = arguments,
            callNow = options.immediate && !timeout,

            later = function() {
                timeout = null;
                if (!options.immediate) fn.apply(context, args);
            };

        clearTimeout(timeout);
        timeout = setTimeout(later, treshold);
        if (callNow) fn.apply(context, args);
    };
};


(function(){
    var i = 0, 
        n = 0,
        f = debounce( function(x) { ++n; console.log("f(" + x + ") = " + n); }, 250);

    var t = setInterval( function () { 
        if(++i == 200) {
            clearInterval(t);
        }
        f(i);
    }, 10);
})();