maishidaSJ/hybrid/html/maps/js/lib/rem.js

!(function(window) {
  /* 设计图文档宽度 */
  var docWidth = 750;
  var doc = window.document,
    docEl = doc.documentElement,
    resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize';
  var recalc = (function refreshRem() {
    var clientWidth = docEl.getBoundingClientRect().width;
    /* 8.55：小于320px不再缩小，11.2：大于420px不再放大 */
    docEl.style.fontSize = Math.max(Math.min(20 * (clientWidth / docWidth), 11.2), 8.55) * 5 + 'px';
    return refreshRem;
  })();
  /* 添加倍屏标识，安卓为1 */
  docEl.setAttribute('data-dpr', window.navigator.appVersion.match(/iphone/gi) ? window.devicePixelRatio : 1);
  if (/iP(hone|od|ad)/.test(window.navigator.userAgent)) {
    /* 添加IOS标识 */
    doc.documentElement.classList.add('ios');
    /* IOS8以上给html添加hairline样式，以便特殊处理 */
    if (parseInt(window.navigator.appVersion.match(/OS (\d+)_(\d+)_?(\d+)?/)[1], 10) >= 8)
      doc.documentElement.classList.add('hairline');
  }
  if (!doc.addEventListener)
    return;
  window.addEventListener(resizeEvt, recalc, false);
  doc.addEventListener('DOMContentLoaded', recalc, false);
})(window);