【学习点滴-js】js 检测浏览器，呈现引擎和平台。

var client = function(){
		//呈现引擎
		var engine = {
			ie : 0,
			gecko : 0,
			webkit : 0,
			khtml : 0,
			opera : 0,
			ver : null
		};
		//浏览器
		var browser = {
			//主要浏览器
			ie : 0,
			firefox : 0,
			konq : 0,
			opera : 0,
			chrome : 0,
			safari : 0,
			//版本号
			ver : null
		};
		
		var system = {
			win : false,
			mac : false,
			x11 : false,
			//移动设备
			iphone : false,
			ipod : false,
			nokiaN  : false,
			winMobile : false,
			macMobile : false,
			//游戏系统
			wii : false,
			ps　:false
		};
		
		
		//检测呈现引擎和浏览器
		var ua  = navigator.userAgent;
		if(window.opera){
			engine.ver = browser.ver = window.opera.version();
			engine.opera = browser.opera = parseFloat(engine.ver);
		}else if(/AppleWebKit\/(\S+)/.test(ua)){
			engine.ver = RegExp["$1"];
			engine.webkit = parseFloat(engine.ver);
			
			if(/Chrome\/(\S+)/.test(ua)){
				browser.ver = RegExp["$1"];
				browser.chrome = parseFloat(browser.ver);
			}else if(/Version\/(\S+)/.test(ua)){
				browser.ver = RegExp["$1"];
				browser.safari = parseFloat(browser.ver);
			}else{
				var safariVersion = 1;
				if(engine.webkit < 100){
					safariVersion = 1;
				}else if(engine.webkit < 312){
					safariVersion = 1.2;
				}else if(engine.webkit < 412){
					safariVersion = 1.3;
				}else{
					safariVersion = 2;
				}
				browser.safari = browser.ver = safariVersion;
			}
		}else if(/KHTML\/(\S+)/.test(ua) || /Konqueror\/([^;]+)/.test(ua)){
			engine.ver = browser.ver = RegExp["$1"];
			engine.khtml = parseFloat(engine.ver);
		}else if(/rv:([^\)]+)\) Gecko\/\d{8}/.test(ua)){
			engine.ver = browser.ver = RegExp["$1"];
			engine.gecko = parseFloat(engine.ver);
			
			//
			if(/Firefox\/(\S+)/.test(ua)){
				browser.ver = RegExp["$1"];
				browser.firefox = parseFloat(browser.ver);
			}
		}else if(/MSIE ([^;]+)/.test(ua)){
			engine.ver = browser.ver = RegExp["$1"];
			engine.ie = browser.ie = parseFloat(browser.ver);
		}
		
		browser.ie = engine.ie;
		browser.opera = engine.opera;
		
		//检测平台		
		var p = navigator.platform;
		system.win = p.indexOf("Win") == 0;
		system.mac = p.indexOf("Mac") == 0;
		system.x11 = (p == "x11") || (p.indexOf("Linux") == 0);
		
		//检测windows平台
		if(system.win){
			if(/Win(?:dows )?([^do]{2})\s?(\d+\.\d+)?/.test(ua)){
				if(RegExp["$1"] == "NT"){
					switch(RegExp["$2"]){
						case "5.0" : 
							system.win = "2000";
							break;
						case "5.1" :
							system.win = "XP";
							break;
						case "6.0" : 
							system.win = "Vista";
							break;
						default :
							system.win = "NT";
							break;							
					}
				}else if(RegExp["$1"] == "9x"){
					system.win = "ME";
				}else{
					system.win = RegExp["$1"];
				}
			}
		}
		
		system.iphone = ua.indexOf("iPhone") > -1;
		system.ipod = ua.indexOf("iPod") > -1;
		system.nokiaN = ua.indexOf("nokiaN") > -1;
		system.winMobile = (system.win =="CE");
		system.macMobile = (system.iphone || system.ipod);
		
		system.wii = ua.indexOf("Wii") > -1;
		system.ps = /playstation/i.test(ua);
		
		return {
			engine : engine,
			browser : browser,
			system : system
		};
	}();