Returns a function, that, as long as it continues to be invoked, will not be triggered. The function will be called after it stops being called for N milliseconds. If `immediate` is passed, trigger the function on the eading edge, instead of the trailing.

debounce.js

// Returns a function, that, as long as it continues to be invoked, will not
// be triggered. The function will be called after it stops being called for
// N milliseconds. If `immediate` is passed, trigger the function on the
// leading edge, instead of the trailing.
function debounce(func, wait, immediate) {
	var timeout;
	return function() {
		var context = this, args = arguments;
		clearTimeout(timeout);
		timeout = setTimeout(function() {
			timeout = null;
			if (!immediate) func.apply(context, args);
		}, wait);
		if (immediate && !timeout) func.apply(context, args);
	};
};