H5 rem自适应
通过rem自适应布局
方案1(主要手机端):
<script>
function adapt(designWidth, rem2px){
var d = window.document.createElement('p')
d.style.width = '1rem'
d.style.display = "none"
var head = window.document.getElementsByTagName('head')[0]
head.appendChild(d)
var defaultFontSize = parseFloat(window.getComputedStyle(d, null).getPropertyValue('width'))
return defaultFontSize
};
!(function(doc, win, designWidth, rem2px) {
var docEl = doc.documentElement,
defaultFontSize = adapt(designWidth, rem2px),
resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize',
recalc = function() {
var clientWidth = win.innerWidth ||
doc.documentElement.clientWidth ||
doc.body.clientWidth
if (!clientWidth) return
if (clientWidth < 750) {
docEl.style.fontSize = clientWidth / designWidth * rem2px / defaultFontSize * 100 + '%'
} else {
docEl.style.fontSize = '625%'
}
}
if (!doc.addEventListener) return
win.addEventListener(resizeEvt, recalc, false)
doc.addEventListener('DOMContentLoaded', recalc, false)
})(document, window, 1920, 100)
//1920 指设计稿尺寸, 100指基准1rem=100px;
//比如:1920的设计稿上某个div的款式100px,则写css样式时写“width:1rem”
</script>
方案2(主要PC端):
<script>
(function(window){
setRem();
function setRem(){
var html = document.documentElement;
var width = html.clientWidth;
if(width > 1920) width = 19.2;
html.style.fontSize = width/19.2 + "px";
};
window.addEventListener('resize',setRem,false);
})(window);
</script>
方案3(未验证,原理说明):
//计算屏幕比例并设置html的font-size
/**
将html字号设置为10个设计像素(一个基准系数,即rem为10 设计稿像素)
设计一个缩放系数,以应对可能出现的适配高清屏要求
*/
(function () {
/**初始化方法
* _standard 设计稿对应的分辨率
* base_DPR 设定最小DPR值
*/
function setInitialRem(_standard, base_DPR) {
//取得当前设备DPR
var dpr = window.devicePixelRatio || 1;
//如果设定了默认最小DPR值
if (base_DPR) {
dpr = dpr >= base_DPR ? dpr : base_DPR;
}
//设定缩放视图比例
var scale = 1 / dpr;
//设直视图缩放比例
document.head.querySelector('meta[name="viewport"]').content = "width=device-width,initial-scale=" + scale + ",minimum-scale=" + scale + ",maximum-scale=" + scale + ",user-scalable=no, shrink-to-fit=no";
//取得当前设备宽度
var device_width = document.documentElement.clientWidth; //window.innerWidth;
//标定原稿设计基准值 当前稿件设计宽度为 iPhone6/6s 375像素
var standard_width = _standard * dpr;
//设定基准单位
var base_value = 10;
//基准系数=设备宽度➗稿件基准宽度✖️设备DPR✖️10
var rem = device_width / standard_width * dpr * base_value;
//设置 REM
document.documentElement.style.fontSize = rem + "px";
}
window.addEventListener("resize", function () {
setInitialRem(375, 1);
});
setInitialRem(375, 1);
})();