Object.extend(Element, {
	getWidth: function(element) {
	   	element = $(element);
	   	return element.offsetWidth; 
	},
	setWidth: function(element,w) {
	   	element = $(element);
    	element.style.width = w +"px";
	},
	setHeight: function(element,h) {
   		element = $(element);
    	element.style.height = h +"px";
	},
	setTop: function(element,t) {
	   	element = $(element);
    	element.style.top = t +"px";
	},
	setSrc: function(element,src) {
    	element = $(element);
    	element.src = src; 
	},
	setHref: function(element,href) {
    	element = $(element);
    	element.href = href; 
	},
	setInnerHTML: function(element,content) {
		element = $(element);
		element.innerHTML = content;
	}
});

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;
}

function showBox(){
    Element.show('overlay');
	var arrayPageSize = getPageSize();
	Element.setHeight('overlay', arrayPageSize[1]);
    center('box');
    return false;
}

function hideBox(){
    Element.hide('box');
    Element.hide('overlay');
    return false;
}

function center(element){
    try{
        element = document.getElementById(element);
    }catch(e){
        return;
    }

    var my_width  = 0;
    var my_height = 0;

    if ( typeof( window.innerWidth ) == 'number' ){
        my_width  = window.innerWidth;
        my_height = window.innerHeight;
    }else if ( document.documentElement && 
             ( document.documentElement.clientWidth ||
               document.documentElement.clientHeight ) ){
        my_width  = document.documentElement.clientWidth;
        my_height = document.documentElement.clientHeight;
    }
    else if ( document.body && 
            ( document.body.clientWidth || document.body.clientHeight ) ){
        my_width  = document.body.clientWidth;
        my_height = document.body.clientHeight;
    }

    element.style.position = 'absolute';
    element.style.zIndex   = 99;

    var scrollY = 0;

    if ( document.documentElement && document.documentElement.scrollTop ){
        scrollY = document.documentElement.scrollTop;
    }else if ( document.body && document.body.scrollTop ){
        scrollY = document.body.scrollTop;
    }else if ( window.pageYOffset ){
        scrollY = window.pageYOffset;
    }else if ( window.scrollY ){
        scrollY = window.scrollY;
    }

    var elementDimensions = Element.getDimensions(element);

    var setX = ( my_width  - elementDimensions.width  ) / 2;
    var setY = ( my_height - elementDimensions.height ) / 2 + scrollY;

    setX = ( setX < 0 ) ? 0 : setX;
    setY = ( setY < 0 ) ? 0 : setY;

    element.style.left = setX + "px";
    element.style.top  = setY + "px";

    element.style.display  = 'block';
}