javascript学习6 - 爱码网

定时器

setInterval(函数,毫秒)  ------> 重复执行

setTimeout(函数,毫秒); ------> 执行一次

<script type="text/javascript">
     window.onload=function(){
            var timer=null;
            i=0;
            function fn1(){
                document.title=i;
                i++;
                if(i>=11){
                    clearInterval(timer);
                }
            }
            timer=setInterval(fn1,50);
      }
</script>

定时器切换背景例子

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>定时器切换背景</title>
        <script type="text/javascript">
            window.onload=function(){
                var oInput=document.getElementsByTagName('input');
                var oBody=document.body;
                var timer=null;
                var num=0;
                var arrImg=['img/1.png','img/2.png','img/3.png','img/4.png'];
                
                oInput[0].onclick=function(){
                    clearInterval(timer);
                    timer=setInterval(function(){
                        oBody.style.background='url('+arrImg[num]+')';
                        num++;
                        num%=arrImg.length;
                    },1000);
                }
                oInput[1].onclick=function(){
                    clearInterval(timer);
                }
            }
        </script>
    </head>
    <body>
        <input type="button" value="更换背景"/>
        <input type="button" value="停止"/>
    </body>
</html>

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