function Document()
{
    this.initialize = initialize;
    this.printYear = printYear;
    this.setBackground = setBackground;
    this.getPath = getPath;
    this.loadXMLDocument = loadXMLDocument;
    
    function initialize()
    {
        this.printYear();
        this.setBackground();
    }
    
    function printYear()
    {
        var text = document.createTextNode(new Date().getFullYear());
        document.getElementById('year').appendChild(text);
    }
    
    function setBackground()
    {
        var image = null;
        
        if (screen.width <= 800)
        {
            image = this.getPath() + 'pics/background_800_600.jpg';
        }
        else if (screen.width <= 1024)
        {
            image = this.getPath() + 'pics/background_1024_768.jpg';
        }
        else if (screen.width <= 1152)
        {
            if (screen.height <= 768)
            {
                image = this.getPath() + 'pics/background_1152_768.jpg';
            }
            else
            {
                image = this.getPath() + 'pics/background_1152_864.jpg';
            }
        }
        else if (screen.width <= 1280)
        {
            if (screen.height <= 720)
            {
                image = this.getPath() + 'pics/background_1280_720.jpg';
            }
            else if (screen.height <= 800)
            {
                image = this.getPath() + 'pics/background_1280_800.jpg';
            }
            else
            {
                image = this.getPath() + 'pics/background_1280_960.jpg';
            }
        }
        else if (screen.width <= 1366)
        {
            image = this.getPath() + 'pics/background_1366_768.jpg';
        }
        else if (screen.width <= 1440)
        {
            if (screen.height <= 960)
            {
                image = this.getPath() + 'pics/background_1440_960.jpg';
            }
            else
            {
                image = this.getPath() + 'pics/background_1440_1080.jpg';
            }
        }
        else if (screen.width <= 1600)
        {
            if (screen.height <= 900)
            {
                image = this.getPath() + 'pics/background_1600_900.jpg';
            }
            else
            {
                image = this.getPath() + 'pics/background_1600_1200.jpg';
            }
        }
        else if (screen.width <= 1920)
        {
            if (screen.height <= 1080)
            {
                image = this.getPath() + 'pics/background_1920_1080.jpg';
            }
            else
            {
                image = this.getPath() + 'pics/background_1920_1440.jpg';
            }
        }
        else if (screen.width <= 2048)
        {
            if (screen.height <= 1152)
            {
                image = this.getPath() + 'pics/background_2048_1152.jpg';
            }
            else
            {
                image = this.getPath() + 'pics/background_2048_1536.jpg';
            }
        }
        else if (screen.width <= 2560)
        {
            if (screen.height <= 1440)
            {
                image = this.getPath() + 'pics/background_2560_1440.jpg';
            }
            else if (screen.height <= 1600)
            {
                image = this.getPath() + 'pics/background_2560_1600.jpg';
            }
            else if (screen.height <= 1920)
            {
                image = this.getPath() + 'pics/background_2560_1920.jpg';
            }
            else
            {
                image = this.getPath() + 'pics/background_2560_2048.jpg';
            }
        }
        else if (screen.width <= 2800)
        {
            image = this.getPath() + 'pics/background_2800_2100.jpg';
        }
        else if (screen.width <= 3200)
        {
            image = this.getPath() + 'pics/background_3200_2400.jpg';
        }
        
        if (image != null)
        {
            document.getElementsByTagName('body')[0]
                .setAttribute('style', 'background-image:url("' + image + '")');
        }
    }
    
    function getPath()
    {
        return document.getElementById('path').content;
    }
    
    function loadXMLDocument(filename)
    {
        var xhttp = null;
        
        if (window.XMLHttpRequest)
        {
            xhttp = new XMLHttpRequest();
        }
        else
        {
            xhttp = new ActiveXObject('Microsoft.XMLHTTP');
        }
        
        xhttp.open('GET', this.getPath() + 'xml/' + filename, false);
        xhttp.send('');
        return xhttp.responseXML;
    }
}