这次给大家带来js实现导航栏的透明渐变，js实现导航栏透明渐变的注意事项有哪些，下面就是实战案例，一起来看一下。
mui内置有H5版本的透明渐变导航控件，教程参考mui官网；透明渐变导航是一种解决滚动条通顶的变通方案，相比双webview，具有更高的性能和更好的动画效果；
下面通过本文给大家分享基于原生JS实现 MUI导航栏透明渐变效果，具体内容详情如下所示：
首先声明：由于backgroundColor的值采用的是RGBA，IE8及以下不支持，所以此效果不支持IE8及以下的浏览器
css代码
body,p,h1{margin: 0;}
.module-layer{
width: 100%;
position: fixed;
top: 0;
left: 0;
z-index: 100000;
}
.module-layer-content{
position: relative;
min-width: 320px;
max-width: 750px;
width: 100%;
margin: 0 auto;
background-color: rgba(255, 0, 0, 0.9);
}
.module-layer-bg{
width: 100%;
height: 100%;
background: #000;
opacity: .7;
position: absolute;
top: 0;
left: 0;
z-index: -1;
}
.layer-head-name{
height: 50px;
line-height: 50px;
text-align: center;
padding: 0 50px;
font-size: 20px;
}
.layer-return,.layer-share{
width: 50px;
height: 50px;
line-height: 50px;
text-align: center;
position: absolute;
top:0;
z-index: 1;
}
.layer-return{left: 0;}
.layer-share{right: 0;}
.fixed-layer{
height: 100%;
display: none;
z-index: 100001;
}
.relative-layer{height: 100%;}
.layer-content{
padding:3%;
position: relative;
top: 20%;
}
.layer-close{
width: 2rem;
height: 2rem;
position: absolute;
top:3%;
right: 3%;
}
.pr {
position:relative;
}
#shop-input::-webkit-input-placeholder {
color:#fff;
}
#shop-input:-moz-placeholder {
color:#fff;
}
#shop-input::-moz-placeholder {
color:#fff;
}
#shop-input:-ms-input-placeholder {
color:#fff;
}
#shop-input {
border:none;
outline:none;
background:transparent;
}
.search-box {
height:30px;
border-radius:20px;
top:10px;
overflow:hidden;
z-index:10;
}
.search-box:after {
content:'';
display:block;
width:100%;
height:30px;
background:#fff;
opacity:.5;
position:absolute;
top:0;
left:0px;
z-index:-1;
}
#shop-input {
height:28px;
line-height:28px;
font-size:16px;
position:absolute;
top:0;
left:30px;
}
.shop-search {
width:16px;
height:16px;
position:absolute;
top:7px;
left:6px;
}
.layer-return{
background: url(images/return.png) no-repeat center center/12px 20px;
}
.layer-share{
background: url(images/share.png) no-repeat center center/20px 30px;
}
a {
-webkit-tap-highlight-color: transparent;
-webkit-touch-callout: none;
-webkit-user-select: none;
}
.module-content{
min-width: 320px;
max-width: 750px;
width: 100%;
margin: 0 auto;
background: #fff;
}
.module-content p:first-child img{margin-top: 0;}
.module-content p img{
display: block;
width: 100%;
margin-top: 10px;
}HTML代码
<header class="module-layer">
<p class="module-layer-content">
<p class="layer-return"></p>
<h1 class="layer-head-name">
<p class="pr search-box">
@@##@@
<input id="shop-input" type="text" placeholder="搜索店内商品" value="" />
</p>
</h1>
<p class="layer-share"></p>
</p>
</header>
<p class="module-content">
<p>@@##@@</p><div class="aritcle_card flexRow">
<div class="artcardd flexRow">
<a class="aritcle_card_img" href="/xiazai/js/8008" title="JS+CSS透明渐变导航栏特效"><img
src="https://img.php.cn/upload/jscode/000/000/003/170908230398254.jpg" alt="JS+CSS透明渐变导航栏特效" onerror="this.onerror='';this.src='/static/lhimages/moren/morentu.png'" ></a>
<div class="aritcle_card_info flexColumn">
<a href="/xiazai/js/8008" title="JS+CSS透明渐变导航栏特效">JS+CSS透明渐变导航栏特效</a>
<p>JS+CSS透明渐变导航栏特效是一款渐变风格的个性网站半透明导航栏动画特效。</p>
</div>
<a href="/xiazai/js/8008" title="JS+CSS透明渐变导航栏特效" class="aritcle_card_btn flexRow flexcenter"><b></b><span>下载</span> </a>
</div>
</div>
<p>@@##@@</p>
<p>@@##@@</p>
<p>@@##@@</p>
<p>@@##@@</p>
<p>@@##@@</p>
<p>@@##@@</p>
<p>@@##@@</p>
</p>JS代码
(function(){
//获取滚动条当前位置
function getScrollTop(){
var scrollTop = 0, bodyScrollTop = 0, documentScrollTop = 0;
if(document.body){
bodyScrollTop = document.body.scrollTop;
}
if(document.documentElement){
documentScrollTop = document.documentElement.scrollTop;
}
scrollTop = (bodyScrollTop - documentScrollTop > 0) ? bodyScrollTop : documentScrollTop;
return scrollTop;
}
//获取CSS样式
function getStyle(element, attr){
if(element.currentStyle){
return element.currentStyle[attr];
}else{
return window.getComputedStyle(element,null)[attr];
}
}
//获取原始backgroundColor值
var color = getStyle(document.getElementsByClassName('module-layer-content')[0],'backgroundColor');
//取到RGB
var colorRgb = color.substring(0,color.lastIndexOf(',') + 1);
//取到A
var colorA = color.substring(color.lastIndexOf(',') + 1,color.length - 1);
//对A判断，如果最终值小于0.9，直接设置为1
if(colorA < 0.9){colorA = 1;}
//设置背景色的A的函数
var setCoverOpacity = function() {
document.getElementsByClassName('module-layer-content')[0].style.background = colorRgb + (((getScrollTop() / 550) > colorA) ? colorA : (getScrollTop() / 550)) + ')';
}
//初始化函数
setCoverOpacity();
//绑定滚动监听事件
window.addEventListener('scroll',setCoverOpacity,false);
}())注意：
不兼容IE8及以下的IE浏览器；
550是滚动条到达位置的最终透明度，此处根据需要自定义；
CSS终背景颜色的RGBA的A是最终透明度
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