JavaScript定时器

定时器

开启定时器

Setinterval间隔型每隔一段时间重复的执行

SetTimeout延时型只执行一次

两种定时器的区别

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script>
        function show(){
            alert('a');
        }
        setInterval(show,1000);//每隔1000毫秒弹出一个a
    </script>
</head>
<body>

</body>
</html>

停止定时器

ClearInterval

clearTimeout

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>Title</title>

    <script>

        window.onload=function(){

            var oBtn1=document.getElementById('btn1');

            var oBtn2=document.getElementById('btn2');

            var timer=null;

          oBtn1.onclick=function(){

            timer=setInterval(function(){

                  alert('a');

              },1000);

          };

          oBtn2.onclick=function(){

              clearInterval(timer);

          }

        };

    </script>

</head>

<body>

<button>

    <input id="btn1" type="button" value="开始"/>

    <input id="btn2" tyPe="button" value="结束"/>

</button>

</body>

</html>