function getPageSize(){
    
    var xScroll, yScroll;
    
    if (window.innerHeight && window.scrollMaxY) {
        xScroll = document.body.scrollWidth;
        yScroll = window.innerHeight + window.scrollMaxY;
    }
    else 
        if (document.body.scrollHeight > document.body.offsetHeight) { // all but Explorer Mac
            xScroll = document.body.scrollWidth;
            yScroll = document.body.scrollHeight;
        }
        else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
            xScroll = document.body.offsetWidth;
            yScroll = document.body.offsetHeight;
        }
    
    var windowWidth, windowHeight;
    if (self.innerHeight) { // all except Explorer
        windowWidth = self.innerWidth;
        windowHeight = self.innerHeight;
    }
    else 
        if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode
            windowWidth = document.documentElement.clientWidth;
            windowHeight = document.documentElement.clientHeight;
        }
        else 
            if (document.body) { // other Explorers
                windowWidth = document.body.clientWidth;
                windowHeight = document.body.clientHeight;
            }
    
    // for small pages with total height less then height of the viewport
    if (yScroll < windowHeight) {
        pageHeight = windowHeight;
    }
    else {
        pageHeight = yScroll;
    }
    
    // for small pages with total width less then width of the viewport
    if (xScroll < windowWidth) {
        pageWidth = windowWidth;
    }
    else {
        pageWidth = xScroll;
    }
    
    arrayPageSize = new Array(pageWidth, pageHeight, windowWidth, windowHeight)
    return arrayPageSize;
}