什么是debounce?
举个例子：
一个input的onChange事件，监听用户输入，当输入停下来的时候，会发起一段请求。（参考百度的做法）
实现如下：
var debounce = function(func, wait, immediate) {
var timeout, result;
return function() {
var context = this, args = arguments;
var later = function() {
timeout = null;
if (!immediate) result = func.apply(context, args);
};
var callNow = immediate && !timeout;
clearTimeout(timeout);
timeout = setTimeout(later, wait);
if (callNow) result = func.apply(context, args);
return result;
};
};
什么是throttle?
举个例子：
我们需要在拖拽的过程中监听当前div的位置，很有可能一秒执行几十次，如果我想提升性能，只监听5次怎么办？
var throttle = function(func, wait) {
var context, args, timeout, result;
var previous = 0;
var later = function() {
previous = new Date;
timeout = null;
result = func.apply(context, args);
};
return function() {
var now = new Date;
var remaining = wait - (now - previous);
context = this;
args = arguments;
if (remaining <= 0) {
clearTimeout(timeout);
timeout = null;
previous = now;
result = func.apply(context, args);
} else if (!timeout) {
timeout = setTimeout(later, remaining);
}
return result;
};
};