/// <summary>
    /// 浏览器屏幕信息类
    /// </summary>
    public class Browser
    {
        /// <summary>  
        /// During static instantiation, only the Netscape flag is checked  
        /// </summary>  
        static Browser()
        {
            _isNavigator = HtmlPage.BrowserInformation.Name.Contains("Netscape");
        }

        /// <summary>  
        /// Flag indicating Navigator/Firefox/Safari or Internet Explorer  
        /// </summary>  
        private static bool _isNavigator;

        /// <summary>  
        /// Provides quick access to the window.screen ScriptObject  
        /// </summary>  
        private static ScriptObject Screen
        {
            get
            {
                ScriptObject screen = (ScriptObject)HtmlPage.Window.GetProperty("screen");

                if (screen == null)
                {
                    throw new InvalidOperationException();
                }

                return screen;
            }
        }

        /// <summary>  
        /// Gets the window object's client width  
        /// </summary>  
        public static double ClientWidth
        {
            get
            {
                return _isNavigator ? (double)HtmlPage.Window.GetProperty("innerWidth")
                    : (double)HtmlPage.Document.Body.GetProperty("clientWidth");
            }

        }

        /// <summary>  
        /// Gets the window object's client height  
        /// </summary>  
        public static double ClientHeight
        {
            get
            {
                return _isNavigator ? (double)HtmlPage.Window.GetProperty("innerHeight")
                    : (double)HtmlPage.Document.Body.GetProperty("clientHeight");
            }
        }

        /// <summary>  
        /// Gets the current horizontal scrolling offset  
        /// </summary>  
        public static double ScrollLeft
        {
            get
            {
                return _isNavigator ? (double)HtmlPage.Window.GetProperty("pageXOffset")
                    : (double)HtmlPage.Document.Body.GetProperty("scrollLeft");
            }
        }

        /// <summary>  
        /// Gets the current vertical scrolling offset  
        /// </summary>  
        public static double ScrollTop
        {
            get
            {
                return _isNavigator ? (double)HtmlPage.Window.GetProperty("pageYOffset")
                    : (double)HtmlPage.Document.Body.GetProperty("scrollHeight");
            }
        }

        /// <summary>  
        /// Gets the width of the entire display  
        /// </summary>  
        public static double ScreenWidth
        {
            get
            {
                return (double)Screen.GetProperty("width");
            }
        }

        /// <summary>  
        /// Gets the height of the entire display  
        /// </summary>  
        public static double ScreenHeight
        {
            get
            {
                return (double)Screen.GetProperty("height");
            }
        }

        /// <summary>  
        /// Gets the width of the available screen real estate, excluding the dock  
        /// or task bar  
        /// </summary>  
        public static double AvailableScreenWidth
        {
            get
            {
                return (double)Screen.GetProperty("availWidth");
            }
        }

        /// <summary>  
        /// Gets the height of the available screen real estate, excluding the dock /// or task bar  
        /// </summary>  
        public static double AvailableScreenHeight
        {
            get
            {
                return (double)Screen.GetProperty("availHeight");
            }
        }

        /// <summary>  
        /// Gets the absolute left pixel position of the window in display coordinates  
        /// </summary>  
        public static double ScreenPositionLeft
        {
            get
            {
                return _isNavigator ? (double)HtmlPage.Window.GetProperty("screenX")
                    : (double)HtmlPage.Window.GetProperty("screenLeft");
            }
        }

        /// <summary>  
        /// Gets the absolute top pixel position of the window in display coordinates  
        /// </summary>  
        public static double ScreenPositionTop
        {
            get
            {
                return _isNavigator ? (double)HtmlPage.Window.GetProperty("screenY")
                    : (double)HtmlPage.Window.GetProperty("screenTop");
            }
        }
    }