MetaHandler.js：移动端适配各种屏幕

MetaHandler.js

!function () {
   var opt = function() {
       var ua = navigator.userAgent,
           android = ua.match(/(Android);?[\s\/]+([\d.]+)?/),
           ipad = ua.match(/(iPad).*OS\s([\d_]+)/),
           ipod = ua.match(/(iPod)(.*OS\s([\d_]+))?/),
           iphone = !ipad && ua.match(/(iPhone\sOS)\s([\d_]+)/),
           os = {},
           uc = ua.match(/UCBrowser+/);
       if (android){ os.android = true, os.version = android[2];}
       if (iphone && !ipod) {os.ios = os.iphone = true, os.version = iphone[2].replace(/_/g, '.');}
       if (ipad) {os.ios = os.ipad = true, os.version = ipad[2].replace(/_/g, '.');}
       if (ipod) {os.ios = os.ipod = true, os.version = ipod[3] ? ipod[3].replace(/_/g, '.') : null;}

       var MetaHandler = function(){
           //MONOSTATE
           if(MetaHandler.prototype.instance){
               return MetaHandler.prototype.instance;
           }
           var me = this;
           var meta = {},_els;

           /**
            * _els
            * meta = {name:{content:String,seriation:Array,store:{property:String},...},...}
            * @method init
            */
           function init(){
               _els = document.getElementsByTagName('meta');
               for(var i=0;i<_els.length;i++){
                   var name = _els[i].name;
                   if(name){
                       meta[name] = {};
                       meta[name].el = _els[i];
                       meta[name].content = _els[i].content;
                       meta[name].seriation = meta[name].content.split(',');
                       meta[name].store = getContentStore(name);
                   }
               }
               return me;
           }
           function getContentStore(name){
               var content = meta[name].seriation,store = {};
               for(var i=0;i<content.length;i++){
                   if(content[i].length<1){
                       content[i] = null;
                       delete content[i];
                       content.length--;
                   }else{
                       var ct = content[i].split('='),
                           pp = ct[0];
                       if(pp){
                           store[pp] = ct[1];
                       }
                   }
               }
               return store;
           }
           this.hasMeta = function(name){
               return meta[name]?1:0;
           }
           this.createMeta = function(name){
               if(!this.hasMeta(name)){
                   var el = document.createElement('meta');
                   el.name = name;
                   document.head.appendChild(el);
                   meta[name] = {};
                   meta[name].el = el;
                   meta[name].content = '';
                   meta[name].seriation = [];
                   meta[name].store = {};
               }
               return me;
           }
           this.setContent = function(name,value){
               meta[name].content = value;
               meta[name].el.content = value;
               return me;
           }
           this.getContent = function(name){
               return meta[name] && meta[name].content;
           }
           function updateContent(name){
               meta[name].content = meta[name].seriation.join(',');
               me.setContent(name,meta[name].content);
               return me;
           }
           this.removeContentProperty = function(name,property){
               var _property = property;
               if(meta[name]){
                   if(meta[name].store[_property]!=null){
                       for(var i = 0;i<meta[name].seriation.length;i++){
                           if(meta[name].seriation[i].indexOf(property+'=')!=-1){
                               meta[name].seriation[i] = null;
                               delete meta[name].seriation[i];
                               break;
                           }
                       }
                   }
                   updateContent(name);
               }
               return me;
           }
           this.getContentProperty = function(name,property){
               return meta[name] && meta[name].store[property];
           }
           this.setContentProperty = function(name,property,value){
               var _property = property,
                   pv = property+'='+value;
               if(meta[name]){
                   if(meta[name].store[_property]!=null){
                       meta[name].store[_property] = value;
                       for(var i = 0;i<meta[name].seriation.length;i++){
                           if(meta[name].seriation[i].indexOf(property+'=')!=-1){
                               meta[name].seriation[i] = pv;
                               break;
                           }
                       }
                   }else{
                       meta[name].store[_property] = value;
                       meta[name].seriation.push(pv);
                   }
                   updateContent(name);
               }
               return me;
           }

           this.fixViewportWidth = function(width,fixBody){
               width = width || me.getContentProperty('viewport','width');
               if(width != 'device-width'){
        	   var dpr = window.devicePixelRatio;
        	   if(uc){
                       var iw = window.innerWidth || width,
                       ow = window.outerWidth/dpr || iw,
                       sw = window.screen.width/dpr || iw,
                       saw = window.screen.availWidth/dpr || iw,
                       ih = window.innerHeight || width,
                       oh = window.outerHeight/dpr || ih,
                       sh = window.screen.height/dpr || ih,
                       sah = window.screen.availHeight/dpr || ih,
                       w = Math.min(iw,ow,sw,saw,ih,oh,sh,sah),
                       ratio = w/width;
                       
                       ratio = Math.min(ratio,dpr);
                   }else{
                       var iw = window.innerWidth || width,
                       ow = window.outerWidth || iw,
                       sw = window.screen.width || iw,
                       saw = window.screen.availWidth || iw,
                       ih = window.innerHeight || width,
                       oh = window.outerHeight || ih,
                       sh = window.screen.height || ih,
                       sah = window.screen.availHeight || ih,
                       w = Math.min(iw,ow,sw,saw,ih,oh,sh,sah),
                       ratio = w/width;
                       ratio = Math.min(ratio,dpr);
                   }
                   //fixBody may trigger a reflow,you should not use it if you could do it in your css
                   if(fixBody){
                       document.body.style.width = width+'px';
                   }
                   //ratio = 1;
                   if(os.android){
                       if(uc){
                	   me.removeContentProperty('viewport','user-scalable')
                           .setContentProperty('viewport','initial-scale',ratio)
                           .setContentProperty('viewport','maximum-scale',ratio);
                       }else{
                	   me.removeContentProperty('viewport','user-scalable')
                           .setContentProperty('viewport','target-densitydpi','device-dpi')
                           .setContentProperty('viewport','initial-scale',ratio)
                           .setContentProperty('viewport','maximum-scale',ratio);
                       }
                       
                   }else if(os.ios && !os.android){
                       me.setContentProperty('viewport','user-scalable','no');
                       if(os.ios && parseInt(os.version)<7){
                           me.setContentProperty('viewport','initial-scale',ratio);
                       }
                   }
               }
           }
           init();
           //MONOSTATE
           MetaHandler.prototype.instance = this;
       };
       return new MetaHandler;
   }();

   // HTML5友情提示 —— 调用自适应屏幕的功能函数
   opt.fixViewportWidth(640);
   
}();

准备一个用px实现的移动页面（宽度固定死的页面），引入metahandler.js框架
1、视口设置
width=640，是根据psd图来设置，有多宽设置多宽（设计图是640的设置640）
<meta content="target-densitydpi=device-dpi,width=640" name="viewport">
2、body设置宽度，是根据psd图来设置，有多宽设置多宽
3. metahandler.js里面参数的设置
调用自适应屏幕的功能函数，640是根据psd图来设置，有多宽设置多宽
opt.fixViewportWidth(640);

<!doctype html>
<html>
<head>
<meta charset="UTF-8">
<title>MetaHandler.js示例 - jingPlus</title>
<meta content="target-densitydpi=device-dpi,width=640" name="viewport">

<style>
	body {
		/*设置跟psd一样的宽度*/
		width: 640px;
		margin: 0 auto;
		background-color: #f0eff4;
	}
	.wrap header {
		position: relative;
		height: 78px;
		line-height: 78px;
		background-color: #f9f9f9;
		font-size: 32px;
		text-align: center;
	}
	.con {
		padding: 24px 17px 0;
	}
	.con nav a {
		float: left;
		width: 146px;
		height: 146px;
		margin-bottom: 10px;
		line-height: 146px;
		font-size: 22px;
		text-align: center;
	}
	.con nav a:nth-child(1) {
		width: 299px;
		background-color: #e66444;
	}
	.con nav a:nth-child(2) {
		margin: 0 7px;
		background-color: #f09056;
	}
	.con nav a:nth-child(3) {
		background-color: #a2c159;
	}
	.con nav a:nth-child(4) {
		background-color: #9178af;
	}
	.con nav a:nth-child(5) {
		margin: 0 7px;
		background-color: #49a7da;
	}
	.con nav a:nth-child(6) {
		margin-right: 7px;
		background-color: #56bc8a;
	}
	.con nav a:nth-child(7) {
		background-color: #d179ad;
	}
</style>
</head>
<body>
	<div class="wrap">
		<header>示例标题</header>
		<section class="con">
			<nav class="clearfix">
				<a href="" title="">一二三四</a>
				<a href="" title="">在线订餐</a>
				<a href="" title="">报修申请</a>
				<a href="" title="">地铁线路</a>
				<a href="" title="">公交站点</a>
				<a href="" title="">测试</a>
				<a href="" title="">今日优惠</a>
			</nav>
		</section>
	</div>
	<!-- 引入MetaHandler -->
	<script type="text/javascript" src="metaHandler.src.js"></script> 
</body>
</html>

本文转自：http://blog.csdn.net/congcong875/article/details/50352123

原文：https://github.com/unbug/generator-webappstarter/blob/master/app/templates/app/src/util/MetaHandler.js?utm_source=tuicool&utm_medium=referral