js 函数节流

function throttle(fn,delay){
var timer = null;
return function (){//使用闭包，保证了全局的timer
var context = this, args = arguments;
clearTimeout(timer);
timer = setTimeout(function (){
fn.apply(context,args);//context保证了fn里的thi
},delay);
};
};


function fn(){
console.log("执行");
}

$("#btn").on("click",throttle(fn, 500));

<input id="btn" type="button"  value="点击"/>