function showBox(){     
	 var arrayPageSize = getPageSize();
	 var myOverlay = document.getElementById('overlay');
		myOverlay.style.display = "block"; 
		myOverlay.style.height =  arrayPageSize[1] +"px";
		myOverlay.style.width =  arrayPageSize[2] +"px";
		
    center('box');     
    return false; 
    
} 
    
function hideBox(){
    document.getElementById('box').style.display = "none";     
    document.getElementById('overlay').style.display = "none";     
    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';
	
    } 
    
    // -----------------------------------------------------------------------------------
 
//
// getPageScroll()
// Returns array with x,y page scroll values.
// Core code from - quirksmode.org
//
function getPageScroll(){
 
        var yScroll;
 
        if (self.pageYOffset) {
               yScroll = self.pageYOffset;
        } else if (document.documentElement && document.documentElement.scrollTop){  // Explorer 6 Strict
               yScroll = document.documentElement.scrollTop;
        } else if (document.body) {// all other Explorers
               yScroll = document.body.scrollTop;
        }
 
        arrayPageScroll = new Array('',yScroll) 
        return arrayPageScroll;
}
 
// -----------------------------------------------------------------------------------
 
//
// getPageSize()
// Returns array with page width, height and window width, height
// Core code from - quirksmode.org
// Edit for Firefox by pHaez
//
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;
}
 
// -----------------------------------------------------------------------------------