javascript防止高频调用的debounce函数

// 返回一个函数，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;
	var later = function() {
	timeout = null;
	if (!immediate) func.apply(context, args);
	};
	var callNow = immediate && !timeout;
	clearTimeout(timeout);
	timeout = setTimeout(later, wait);
	if (callNow) func.apply(context, args);
	};
};

// Usage
var myEfficientFn = debounce(function() {
	// All the taxing stuff you do
}, 250);
window.addEventListener('resize', myEfficientFn);