手机布局自适应

mobile-initial-scale

(function(win){
    		var dpr, rem, scale;
			var docEl = document.documentElement;
			var fontEl = document.createElement('style');
			var metaEl = document.querySelector('meta[name="viewport"]');

			dpr = win.devicePixelRatio || 1;
			rem = docEl.clientWidth * 2 / 10;
			scale = 1 / dpr;


			// 设置viewport，进行缩放，达到高清效果
			metaEl.setAttribute('content', 'width=' + dpr * docEl.clientWidth + ',initial-scale=' + scale + ',maximum-scale=' + scale + ', minimum-scale=' + scale + ',user-scalable=no');

			// 设置data-dpr属性，留作的css hack之用
			docEl.setAttribute('data-dpr', dpr);

			// 动态写入样式
			docEl.firstElementChild.appendChild(fontEl);
			fontEl.innerHTML = 'html{font-size:' + rem + 'px!important;}';

			// 给js调用的，某一dpr下rem和px之间的转换函数
			win.rem2px = function(v) {
			    v = parseFloat(v);
			    return v * rem;
			};
			win.px2rem = function(v) {
			    v = parseFloat(v);
			    return v / rem;
			};

			win.dpr = dpr;
			win.rem = rem;

    	})(window);