《JavaScript高级语言设计》(第三版)学习笔记(5)

来源：互联网发布：mac物理地址不匹配编辑：程序博客网时间：2024/06/09 18:24

客户端能力检测和客户端识别

能力检测基本模式

if(object.propertyInQuestion){//方法，如果浏览器不支持此方法则为false    调用方法}function isHaveSortMethod(object){    return typeof object.ort == "function";}//检测某个对象的特性是否存在function isHostMethod(object,property){    var t = typeof object[property];    return t == 'function'||(!!(t == 'object'&& object[property]) || t == 'unknown');}//确定浏览器是否支持Netscape风格的插件var hasNSPlugins = !!(navigator.plugins && navigator.plugins.length);//确定浏览器是否具有DOM1级的能力var hasDOM1 = !!(document.getElementById && document.createElement && document.getElementByTagName);//IE8以及更早的版本存在一个bug，如果摸个实例属性与[[Enumerable]]标记为false的摸个原型属性同名，则该实例属性将不会出现在for-in循环中var hasDontEnumQuirk = function(){    var o = {toString : function(){}};    for(var prop in o){        if(prop == "toString"){            return false;        }    }    return true;}();//Safari3以前版本会枚举被隐藏的属性var hasEnumShadowQuirk = function(){    var o = {toString : function(){}};    var count = 0;    for(var prop in o){        if(prop == "toString"){            count++;        }    }    return (count > 1);}();

//用户代理检测脚本var client = function(){    var engine = {        ie : 0,        gecko : 0,        webkit : 0,        khtml : 0,        opera : 0,        ver : null    };    var browser = {        ie : 0,        firefox : 0,        safari : 0,        konq : 0,        opera : 0,        chrome : 0,        ver : null    };    var system = {        win : false,        mac : false,        x11 : false,        iphone : false,        ipod : false,        ipad : false,        ios : false,        android : false,        nokiaN : false,        winMobile : false,        wii : false,        ps : false    };    var ua = navigator.userAgent;    if(window.opera){        enegine.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);        engine.webkit = parseFloat(engine.ver);        //确定Chrome还是Safari        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 {        //近似地确定版本号            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 = browser.konq = parseFloat(engine.ver);    }else if (/rv:([^\)]+)\) Gecko\/\d{8}/.test(ua)){        engine.ver = RegExp["$1"];        engine.gecko = parseFloat(engine.ver);        //确定是不是Firefox        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(engine.ver);    }    //检测浏览器    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 操作系统    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;                    case "6.1":                        system.win = "7";                        break;                    default:                        system.win = "NT";                        break;                }            } else if (RegExp["$1"] == "9x"){                system.win = "ME";            } else {                system.win = RegExp["$1"];            }        }    }    //移动设备    system.iphone = ua.indexOf("iPhone") > -1;    system.ipod = ua.indexOf("iPod") > -1;    system.ipad = ua.indexOf("iPad") > -1;    system.nokiaN = ua.indexOf("NokiaN") > -1;    //windows mobile    if (system.win == "CE"){        system.winMobile = system.win;    } else if (system.win == "Ph"){        if(/Windows Phone OS (\d+.\d+)/.test(ua)){;            system.win = "Phone";            system.winMobile = parseFloat(RegExp["$1"]);        }    }    //检测iOS 版本    if (system.mac && ua.indexOf("Mobile") > -1){        if (/CPU (?:iPhone )?OS (\d+_\d+)/.test(ua)){        system.ios = parseFloat(RegExp.$1.replace("_", "."));    } else {        system.ios = 2; //不能真正检测出来，所以只能猜测    }    //检测Android 版本    if (/Android (\d+\.\d+)/.test(ua)){        system.android = parseFloat(RegExp.$1);    }    //游戏系统    system.wii = ua.indexOf("Wii") > -1;    system.ps = /playstation/i.test(ua);    //返回这些对象    return {    engine: engine,    browser: browser,    system: system    };}();

//DOM能力检测var hasXmlDom = document.implementation.hasFeature("XML", "1.0");//第一个为功能，第二个为版本号

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