【JavaScript高级程序设计】15、DOM扩展

contains方法

<!DOCTYPE html>
<html>
<head>
    <title>Contains Example 2</title>
    <script type="text/javascript" src="client.js"></script>
</head>
<body>

    <input type="button" value="Does html contain body?" onclick="getContains()">

    <script type="text/javascript">
    
        function contains(refNode, otherNode)
        {
            //首先判断参数节点是不是含有contains函数，并且检查版本号，在webkit<522的版本中
            //contains无法正常使用
            if (typeof refNode.contains == "function" && 
                    (!client.engine.webkit || client.engine.webkit >= 522))
            {
                //判断refNode是否包含otherNode
                return refNode.contains(otherNode);
            } 
            else if (typeof refNode.compareDocumentPosition == "function")
            {
                return !!(refNode.compareDocumentPosition(otherNode) & 16);
            } 
            else 
            {
                //循环遍历父节点，直到找到对应的节点，用来判断是否是父节点
                var node = otherNode.parentNode;
                do 
                {
                    if (node === refNode)
                    {
                        return true;
                    } 
                    else 
                    {
                        node = node.parentNode;
                    }
                } while (node !== null);
                return false;
            }
        }
    
        function getContains()
        {
            alert(contains(document.documentElement, document.body));
        }

    </script>
</body>
</html>

这里注意有一个小的js文件client.js

var client = function(){

    //rendering engines
    var engine = {            
        ie: 0,
        gecko: 0,
        webkit: 0,
        khtml: 0,
        opera: 0,

        //complete version
        ver: null  
    };
    
    //browsers
    var browser = {
        
        //browsers
        ie: 0,
        firefox: 0,
        safari: 0,
        konq: 0,
        opera: 0,
        chrome: 0,
        safari: 0,

        //specific version
        ver: null
    };

    
    //platform/device/OS
    var system = {
        win: false,
        mac: false,
        x11: false,
        
        //mobile devices
        iphone: false,
        ipod: false,
        ipad: false,
        ios: false,
        android: false,
        nokiaN: false,
        winMobile: false,
        
        //game systems
        wii: false,
        ps: false 
    };    

    //detect rendering engines/browsers
    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);
        
        //figure out if it's Chrome or 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 {
            //approximate version
            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);
        
        //determine if it's 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);
    }
    
    //detect browsers
    browser.ie = engine.ie;
    browser.opera = engine.opera;
    

    //detect platform
    var p = navigator.platform;
    system.win = p.indexOf("Win") == 0;
    system.mac = p.indexOf("Mac") == 0;
    system.x11 = (p == "X11") || (p.indexOf("Linux") == 0);

    //detect windows operating systems
    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"];
            }
        }
    }
    
    //mobile devices
    system.iphone = ua.indexOf("iPhone") > -1;
    system.ipod = ua.indexOf("iPod") > -1;
    system.ipad = ua.indexOf("iPad") > -1;
    system.nokiaN = ua.indexOf("NokiaN") > -1;
    system.winMobile = (system.win == "CE");
    
    //determine iOS version
    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;  //can't really detect - so guess
        }
    }
    
    //determine Android version
    if (/Android (\d+\.\d+)/.test(ua)){
        system.android = parseFloat(RegExp.$1);
    }
    
    //gaming systems
    system.wii = ua.indexOf("Wii") > -1;
    system.ps = /playstation/i.test(ua);
    
    //return it
    return {
        engine:     engine,
        browser:    browser,
        system:     system        
    };

}();

 

运行结果：

 

posted @ 2016-07-27 15:29  cutter_point  阅读(119)  评论(0)    收藏  举报