text: //rem设置
  (function(doc, win) {
  	var docEl = doc.documentElement,
  		resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize',
  		recalc = function() {
  			var clientWidth = docEl.clientWidth;
  			if (!clientWidth) return;
  			docEl.style.fontSize = 20 * (clientWidth / 320) + 'px';
  			//宽与高度
  			document.body.style.height = clientWidth * (900 / 1440) + "px"
  		};
  	win.addEventListener(resizeEvt, recalc, false);
  	doc.addEventListener('DOMContentLoaded', recalc, false);
  })(document, window);