using with onscroll, onresize etc.

rarely.js

(function(ns) {


ns.rarely = rarely();

function rarely() {
	var timer = null;

	return rarely;

	function rarely(f, every) {
		every = every || 100;
		if (!timer) {
			f();
			timer = setTimeout(function() {
				f();
				timer = null;
			}, every);
		}
	}
}

	
})(this);

$(document).scroll(function() {
    rarely(function() {
        console.log('call!');
    }, 500);
});