<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>滚动事件</title><script src="https://code.jquery.com/jquery-2.2.4.min.js"></script><style>img{position:fixed;top:640px;left: 1200px;display:none;}#box{width:1000px;height:1200px;margin:0 auto;border:1px solid red;overflow:hidden;}</style><script>/*$(obj).position 获取定位的位置$(obj).scrollTop(0)$(obj).animate({},时间)$(window).scroll(function(){//窗口的滚动事件})；*/$(function(){$(window).scroll(function(){var value=$('body,html').scrollTop();if(value>300){$('img').fadeIn(300);}else{$('img').fadeOut(300);}});$('img').click(function(){$('body,html').animate({'scrollTop':0},'slow')})})</script>
</head>
<body>
<div id="box"></div>
<img src="images/a1.png" alt="箭头">
</body>
</html>
)
和text()的区别)
