1.rem.js内容

! function(n) {
            var e = n.document,
    t = e.documentElement,
    i = 720,
    d = i / 100,
    o = "orientationchange" in n ? "orientationchange" : "resize",
    a = function() {
    var n = t.clientWidth || 320;
    n > 720 && (n = 720);
    t.style.fontSize = n / d + "px"
    };
            e.addEventListener && (n.addEventListener(o, a, !1), e.addEventListener("DOMContentLoaded", a, !1))

}(window);

2.项目目录

3.在main.js 中引入

4.直接使用