flexible.js -->文件可以在这里下载，移动端自适应+rem布局

(function flexible(window, document) {
var docEl = document.documentElement
var dpr = window.devicePixelRatio || 1

// adjust body font size
function setBodyFontSize() {
    if (document.body) {
        document.body.style.fontSize = (12 * dpr) + 'px'
    } else {
        document.addEventListener('DOMContentLoaded', setBodyFontSize)
    }
}
setBodyFontSize();

// set 1rem = viewWidth / 10
function setRemUnit() {
    var rem = docEl.clientWidth / 10
    docEl.style.fontSize = rem + 'px'
}

setRemUnit()

// reset rem unit on page resize
window.addEventListener('resize', setRemUnit)
window.addEventListener('pageshow', function(e) {
    if (e.persisted) {
        setRemUnit()
    }
})

// detect 0.5px supports
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))