dz_farming_relink/rem.js

! function(win) {
	function resize() {
		var deviceWidth = document.documentElement.clientWidth;
		if(deviceWidth > 750) deviceWidth = 750;
		document.documentElement.style.fontSize = Math.floor(deviceWidth / 7.5) + 'px';
	}
	var v, initial_scale, timeCode, dom = win.document,
		domEle = dom.documentElement,
		viewport = dom.querySelector('meta[name="viewport"]'),
		flexible = dom.querySelector('meta[name="flexible"]');
	if(viewport) {
		//viewport：
		var o = viewport.getAttribute("content").match(/initial\-scale=(["']?)([\d\.]+)\1?/);
		if(o) {
			initial_scale = parseFloat(o[2]);
			v = parseInt(1 / initial_scale);
		}
	} else {
		if(flexible) {
			var o = flexible.getAttribute("content").match(/initial\-dpr=(["']?)([\d\.]+)\1?/);
			if(o) {
				v = parseFloat(o[2]);
				initial_scale = parseFloat((1 / v).toFixed(2))
			}
		}
	}
	if(!v && !initial_scale) {
		var n = (win.navigator.appVersion.match(/android/gi), win.navigator.appVersion.match(/iphone/gi));
		v = win.devicePixelRatio;
		v = n ? v >= 3 ? 3 : v >= 2 ? 2 : 1 : 1, initial_scale = 1 / v
	}
	//没有viewport标签的情况下
	if(domEle.setAttribute("data-dpr", v), !viewport) {
		if(viewport = dom.createElement("meta"), viewport.setAttribute("name", "viewport"), viewport.setAttribute("content", "initial-scale=" + initial_scale + ", maximum-scale=" + initial_scale + ", minimum-scale=" + initial_scale + ", user-scalable=no"), domEle.firstElementChild) {
			domEle.firstElementChild.appendChild(viewport)
		} else {
			var m = dom.createElement("div");
			m.appendChild(viewport), dom.write(m.innerHTML)
		}
	}
	win.dpr = v;
	win.addEventListener("resize", function() {
		clearTimeout(timeCode), timeCode = setTimeout(resize, 300)
	}, false);
	win.addEventListener("pageshow", function(b) {
		b.persisted && (clearTimeout(timeCode), timeCode = setTimeout(resize, 300))
	}, false);
	/* 个人觉得没必要完成后就把body的字体设置为12
	"complete" === dom.readyState ? dom.body.style.fontSize = 12 * v + "px" : dom.addEventListener("DOMContentLoaded", function() {
	 //dom.body.style.fontSize = 12 * v + "px"
	}, false);
	*/
	resize();
}(window);