function centering_popup(divid,fadediv)
{
	//Centering popup div		
	   var frameWidth = getFrameWidth();
       var frameHeight = getFrameHeight();
	   
	   var layerWidth = getLayerWidth(divid);
	   var layerHeight = getLayerHeight(divid);
	   
		
		document.getElementById(divid).style.top = ((frameHeight/2) - (layerHeight/2))+"px";
        document.getElementById(divid).style.left = ((frameWidth/2) - (layerWidth/2))+"px";
		
		
		
		//following will display popup exactly infront of screen irrespective of scroll on page
	centerElement(document.getElementById(divid),0,true);
	centerElement(document.getElementById(fadediv),0,true);
	
	
	 window.onresize = function() {
            centerElement(document.getElementById(fadediv), 0, true);
            centerElement(document.getElementById(divid), 0, true);
          
            };
            
        window.onscroll = function() {
            centerElement(document.getElementById(fadediv), 0, true);
            centerElement(document.getElementById(divid), 0, true);

        };
		
	
		
}



    function getScrollXY(){
        var scrOfX = 0, scrOfY = 0;
        if( typeof( window.pageYOffset ) == 'number' ) {
            //Netscape compliant
            scrOfY = window.pageYOffset;
            scrOfX = window.pageXOffset;
        } else if( document.body && ( document.body.scrollLeft || document.body.scrollTop ) ) {
            //DOM compliant
            scrOfY = document.body.scrollTop;
            scrOfX = document.body.scrollLeft;
        } else if( document.documentElement && ( document.documentElement.scrollLeft || document.documentElement.scrollTop ) ) {
            //IE6 standards compliant mode
            scrOfY = document.documentElement.scrollTop;
            scrOfX = document.documentElement.scrollLeft;
        }
        return [ scrOfX, scrOfY ];
        }

function getLayerHeight(id) {
        if (document.all) {
            gh = document.getElementById(id).offsetHeight;  
        }
        else {
            gh = document.getElementById(id).offsetHeight;  //-5;
        }
        return gh;
    }
	
function getLayerWidth(id) {
        gw = document.getElementById(id).offsetWidth;
        return gw;
    }
	
	function getViewportDimensions() {
        var intH = 0, intW = 0;
        
        if(self.innerHeight) {
           intH = window.innerHeight;
           intW = window.innerWidth;
        } 
        else {
            if(document.documentElement && document.documentElement.clientHeight) {
                intH = document.documentElement.clientHeight;
                intW = document.documentElement.clientWidth;
            }
            else {
                if(document.body) {
                    intH = document.body.clientHeight;
                    intW = document.body.clientWidth;
                }
            }
        }

        return {
            height: parseInt(intH, 10),
            width: parseInt(intW, 10)
        };
    }

    function centerElement(elem,add,noleft) {
        var viewport = getViewportDimensions();
        var left = (viewport.width == 0) ? 50 : parseInt((viewport.width - elem.offsetWidth) / 2, 10);
        var top = (viewport.height == 0) ? 50 : parseInt((viewport.height - elem.offsetHeight) / 2, 10);
        var scroll = getScrollXY();
        //alert(scroll[1]);

        if(!noleft) {
            elem.style.left = (left + add) + 'px';
        }
        elem.style.top = (top + add + scroll[1]) + 'px';

        viewport, left, top, elem = null;    
    }
	
	
function getFrameWidth() {
        var frameWidth = document.documentElement.clientWidth;
        if (self.innerWidth) // Als de browser deze manier van aanroepen hanteerd
        {
            frameWidth = self.innerWidth; // Haal de frame-width op
        }
        else if (document.documentElement && document.documentElement.clientWidth)  // Als de browser deze manier van aanroepen hanteerd
        {
            frameWidth = document.documentElement.clientWidth; // Haal de frame-width op
        }
        else if (document.body)  // Als de browser deze manier van aanroepen hanteerd
        {
            frameWidth = document.body.clientWidth; // Haal de frame-width op
        }
        else return;
        return frameWidth;
    }
	
	
	    function getFrameHeight() {
        var frameHeight = document.documentElement.clientHeight;
        if (self.innerWidth) // Als de browser deze manier van aanroepen hanteerd
        {
            frameHeight = self.innerHeight; // Haal de frame-height op
        }
        else if (document.documentElement && document.documentElement.clientWidth)  // Als de browser deze manier van aanroepen hanteerd
        {
            frameHeight = document.documentElement.clientHeight; // Haal de frame-height op
        }
        else if (document.body)  // Als de browser deze manier van aanroepen hanteerd
        {
            frameHeight = document.body.clientHeight; // Haal de frame-height op
        }
        else return;
        return frameHeight;
    }