flexible.js

Posted 2020-12-09 这么神奇

(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))