js 实现导航栏滑动透明渐变样式
来源:blog.csdn.net 发布时间:2019-08-30 01:29
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width,initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no" /> <title>js 实现导航栏滑动渐变样式</title> <style type="text/css"> *{ padding: 0; margin: 0; } img{ width: 100%; } header { position: fixed; left: 0; top: 0; right: 0; z-index: 50; height: 40px; text-align: center; background: rgba(255,255,255,0); color: rgba(66,66,66,0); font-size:20px; line-height: 40px; } </style> </head> <body> <header id="header">首页</header> <img src="http://xxiaoyuan.top/static/img/banner/banner1.jpg"/> <img src="http://xxiaoyuan.top/static/img/banner/banner1.jpg"/> <img src="http://xxiaoyuan.top/static/img/banner/banner1.jpg"/> <img src="http://xxiaoyuan.top/static/img/banner/banner1.jpg"/> <img src="http://xxiaoyuan.top/static/img/banner/banner1.jpg"/> <img src="http://xxiaoyuan.top/static/img/banner/banner1.jpg"/> <img src="http://xxiaoyuan.top/static/img/banner/banner1.jpg"/> <img src="http://xxiaoyuan.top/static/img/banner/banner1.jpg"/> <img src="http://xxiaoyuan.top/static/img/banner/banner1.jpg"/> </body> <script> window.onscroll=function(){ var h =document.documentElement.scrollTop||document.body.scrollTop; console.log(h*2.5); //控制台查看监听滚动 var headerTop =document.getElementById("header"); if( h >=40) { //header的高度是40px; headerTop.style.background="#fff"; headerTop.style.color="rgba(66,65,66,1)"; }else{ if(h<10){ //40*2.5=100;这样透明度就可以由0渐变到100%； headerTop.style.background="rgba(255,255,255,0.0"+h*2.5+")"; headerTop.style.color="rgba(66,66,66,0.0"+h*2.5+")"; }else if(h>10 && h<= 40){ headerTop.style.background="rgba(255,255,255,0."+h*2.5+")"; headerTop.style.color="rgba(66,66,66,0."+h*2.5+")"; } } }; </script> </html> |