1.setInterval被调用后，就会被加入到定时器执行队列中等待绑定的函数被执行，也就是你设置的interval时间只会有效一次
2.想要实现你说的功能，请使用setTimeout函数

function flip(obj){ var timeout=Math.round(Math.random()*1000+1000); clearTimeout(obj.flip); obj.flip=setTimeout(function timeoutFun(){ var oTop=parseInt(getStyle(obj,'top')); oTop==0?doMove(obj,'top',10,-100):doMove(obj,'top',10,0); timeout=Math.round(Math.random()*1000+1000); obj.flip=setTimeout(timeoutFun,timeout); },timeout); }

function flip(obj){ var timer = 0;//第一次随便给个时间间隔 obj.flip=setInterval(function(){ var oTop=parseInt(getStyle(obj,'top')); oTop==0?doMove(obj,'top',10,-100):doMove(obj,'top',10,0); timer = Math.round(Math.random()*1000+1000);//后面每次执行时都会重新生成一个时间间隔 },timer) }

稍微抽象一下：

function repeatJob(jobFunc, intervalGenerator) { var lastTime = 0; var interval = 0; var seed = 0; function loop() { var now = new Date(); if(now - lastTime > interval) { lastTime = now; interval = intervalGenerator() jobFunc(); } seed = requestAnimationFrame(loop) } return { start: function() { seed = requestAnimationFrame(loop) }, stop: function() { cancelAnimationFrame(seed); } } } function intervalGenerator() { return Math.round(Math.random()*1000+1000); } function job() { console.log('this job repeats'); var oTop=parseInt(getStyle(obj,'top')); oTop==0?doMove(obj,'top',10,-100):doMove(obj,'top',10,0); } var r = repeatJob(job, intervalGenerator); r.start(); //r.stop();