触发onscroll事件
<!DOCTYPE html>
<html>
<head>
<title></title>
<style type="text/css">
*{margin:0 0;}
.my_menu{
width:100%;
height:70px;
background:#ccc;
line-height:70px;
text-align:center;
}
.my_body{
width:100%;
height:1600px;
background:pink;
}
input{
border:1px solid #ccc;
width:500px;
height:30px;
border-radius:10px;
outline:none;
padding:2px 20px;
font-size:20px;
}
.fix_menu{
width:100%;
height:70px;
background:#ccc;
line-height:70px;
text-align:center;
position:fixed;
display:none;
top:0;
}
</style>
</head>
<body>
<div class="my_menu">
<input type="" name="">
</div>
<div class="fix_menu">
<input type="" name="">
</div>
<div class="my_body">
</div>
<script type="text/javascript">
window.onload=function(){
var dis_menu=document.getElementsByClassName('fix_menu');
//当滚动栏坐标大于100px时触发事件
window.onscroll=function(){
if(document.documentElement.scrollTop>100){
dis_menu[0].style.display='block';
}
else{
dis_menu[0].style.display='none';
}
}
}
</script>
</body>
</html>