window.onload = function () {
setRem(750, 100);
};
window.onresize = function () {
setRem(750, 100);
};
function setRem(designWidth, designRem) {
let html = document.getElementsByTagName("html")[0];
let clientWidth = document.body.clientWidth || document.documentElement.clientWidth;
html.style.fontSize = designRem * clientWidth / designWidth + "px";
}
750的设计稿,根据屏幕实际大小按比例缩放 fontSize.