PX轉REM

<script>
    var clientWidth;
    var px;
    (function (doc, win) {
        var docEl = doc.documentElement,
            resizeEvt = ‘orientationchange‘ in window ? ‘orientationchange‘ : ‘resize‘,
            recalc = function () {
                clientWidth = docEl.clientWidth;
                
 
var clientHeight = docEl.clientHeight;
                px = 100 * (clientWidth / 640);
                if (!clientWidth) return;
                docEl.style.fontSize = 100 * (clientWidth / 640) + ‘px‘;
            };
        recalc();
        if (!doc.addEventListener) return;
        win.addEventListener(resizeEvt, recalc, 
 
false);
        doc.addEventListener(‘DOMContentLoaded‘, recalc, false);
    })(document, window);
</script>

PX轉REM