js响应式
rem辅助响应式布局：其实就是指在HTML页面的大小不断变化的时候，里面的宽、高、字体等等也随之变化，主要是通过获取window.innerwidth的值来进行判断，7.5rem===100%===750px。
js响应式：就是通过navigator.userAgent.indexOf('Android')来获取不同的客户端版本，例如‘Android’,然后使用 window.resize()=function(){} 返回不同样式给客户端.
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" />
<style type="text/css">
*{
margin: 0;
padding: 0;
box-sizing: border-box;
}
#div1{
/*7.5rem===100%*/
width: 3.75rem;
height: 1rem;
background: skyblue;
font-size: .7rem;
}
</style>
</head>
<body>
<div id="div1">
helloworld
</div>
<script>
// window.innerWidth === 768 === 7.5
// ?1rem === 768/7.5 === 1.x
//
//html字体大小最小是10px,再小就不行。
var html = document.querySelector('html')
html.style.fontSize = window.innerWidth/7.5 + 'px'
window.onresize = function(e){
console.log(e)
console.log(window)
html.style.fontSize = window.innerWidth/7.5 + 'px'
} </script>
</body>
</html>
rem辅助响应式布局
<!DOCTYPE html>
<html class="mobile">
<head>
<meta charset="UTF-8">
<title></title>
<style type="text/css">
.mobile #div1{
background: skyblue;
}
.pc #div1{
background: pink;
}
.pad #div1{
background: salmon;
}
#div1{
height: 100px;
}
.iphone #div1{
background: yellow;
}
.android #div1{
background: seagreen;
}
</style>
</head>
<body>
<div id="div1" > </div> <script type="text/javascript">
var html = document.querySelector('html') function resize(){
var screneLength = window.innerWidth;
html.style.fontSize = window.innerWidth/7.5 + 'px'
if(screneLength>640&&screneLength<960){
html.className = 'pad'
}else if(screneLength>=960){
html.className = 'pc'
}else{
html.className = 'mobile'
} if(navigator.userAgent.indexOf('Android')!==-1){
html.className = html.className + ' android'
}else if(navigator.userAgent.indexOf('iPhone')!==-1){
html.className = html.className + ' iphone'
}else if(navigator.userAgent.indexOf('iPad')!==-1){
html.className = html.className + ' ipad'
}
}
resize()
window.onresize = function(e){ resize()
}
</script>
</body>
</html>
js响应式