(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() { // 这里默认是10等份，手动改为24，此时1rem=1920/24px即80px。（设计稿是1920px的） var rem = docEl.clientWidth / 24; 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);