（十八）淘宝Rem布局方案
1：lib-flexible
(function flexible (window, document) {
var docEl = document.documentElement
var dpr = window.devicePixelRatio || 1
function setBodyFontSize () {
if (document.body) {
document.body.style.fontSize = (12 * dpr) + 'px'
}
else {
document.addEventListener('DOMContentLoaded', setBodyFontSize)
}
}
setBodyFontSize();
function setRemUnit () {
var rem = docEl.clientWidth / 10
docEl.style.fontSize = rem + 'px'
}
setRemUnit()
window.addEventListener('resize', setRemUnit)
window.addEventListener('pageshow', function (e) {
if (e.persisted) {
setRemUnit()
}
})
if (dpr >= 2) {
var fakeBody = document.createElement('body')
var testElement = document.createElement('div')
testElement.style.border = '.5px solid transparent'
fakeBody.appendChild(testElement)
docEl.appendChild(fakeBody)
if (testElement.offsetHeight === 1) {
docEl.classList.add('hairlines')
}
docEl.removeChild(fakeBody)
}
}(window, document))
手淘多年总结出的移动端适配方案
动态改写<meta>标签并且动态改写font-size
