计时器

setInterval  ---下计时器

<script>
$(function(){
    var n=0;
    function run(){
        n=n+1;
        document.title=n;  //浏览器标签栏显示标题
    }
    setInterval(run,2000);
});
</script>

clearInterval  ---清除计时器

var interval = setInterval(run,1000);  //每隔一秒执行一次run()
 
$("").click(function(){  //点击暂停按钮
    if(interval){
        clearInterval(interval);
        interval = null;
    }
});
$("").click(function(){  //点击继续按钮
    if(interval){
        clearInterval(interval);
        interval = null;
    }
    interval = setInterval(run,1000);
});
 
function run(){
   
}