1

/*頁面大小自適應*/
(function () {
    var b = document.documentElement,
    a = function () {
        var a = b.getBoundingClientRect().width;
        b.style.fontSize = (100/1080) * (a >= 750 ? 750 : a) + "px"
    }, c = null;
    window.addEventListener("resize", function () {
        clearTimeout(c);
        c = setTimeout(a, 300)
    });
    a();
})();

2

/* rem.js文件內(nèi)容 */
(function () {
    var html = document.documentElement;

    function onWindowResize() {
        html.style.fontSize = html.getBoundingClientRect().width / 20 + 'px';
    }

    window.addEventListener('resize', onWindowResize);
    onWindowResize();
})();

3.rem配置參數(shù)

rem配置參考：

html {font-size:10px}
@media screen and (min-width:480px) and (max-width:639px) {
    html {
        font-size: 15px
    }
}
@media screen and (min-width:640px) and (max-width:719px) {
    html {
        font-size: 20px
    }
}
@media screen and (min-width:720px) and (max-width:749px) {
    html {
        font-size: 22.5px
    }
}
@media screen and (min-width:750px) and (max-width:799px) {
    html {
        font-size: 23.5px
    }
}
@media screen and (min-width:800px) and (max-width:959px) {
    html {
        font-size: 25px
    }
}
@media screen and (min-width:960px) and (max-width:1079px) {
    html {
        font-size: 30px
    }
}
@media screen and (min-width:1080px) {
    html {
        font-size: 32px
    }
}