function popitup(url, win_width, win_height) 
{
	var newwindow ="";
	var par3="";
	if (newwindow.location && !newwindow.closed) 
	{
		newwindow.location.href = url;
		win_left = (screen.width - win_width)/2;
		win_top = (screen.height - win_height)/2;
		win_width = win_width + 20 ;
		win_height = win_height + 20 ;
		if(GetBrowser == 1)
		{
			newwindow.left =  win_left;
			newwindow.top =  win_top;
		}
		else
		{
			newwindow.screenX =  win_left;
			newwindow.screenY =  win_top;
		}
		newwindow.width = win_width;
		newwindow.height = win_height ;
		newwindow.focus(); 
	}
	else
	{
		win_left = (screen.width - win_width)/2;
		win_top = (screen.height - win_height)/2;
		win_width = win_width + 20 ;
		win_height = win_height + 20 ;
		//win_width = win_width + (window.outerWidth - window.innerWidth);
		//win_height = win_height + (window.outerHeight - window.innerHeight);
		if (win_width >= screen.width || win_height > screen.height)
		{
			newwindow=window.open(url,'htmlname', 'width=800, height=600, resizable=1, status=0, toolbar=0,scroll=1');
		}
		else
		{
			if (GetBrowser() == 1)
			{
				par3 = "left = " + win_left + ", top = " + win_top  + ", width=" + win_width + ", height=" + win_height + ", resizable=1, status=0, toolbar=0";
				newwindow=window.open(url,"htmlname",par3);
			}else
			{
				par3 = "screenX = " + win_left + ", screenY = " + win_top + ", Width=" + win_width + ", Height=" + win_height + ", resizable=1, status=0, toolbar=0";
				newwindow=window.open(url,'htmlname',par3);
			}
		}
		newwindow.focus();
	}
}
   
function tidy()
{
	if (newwindow.location && !newwindow.closed) 
	{
	   newwindow.close(); 
	}
}

function GetBrowser()
{
	//returns 1 is browser is IE or else return 0 for a non IE Browser and -1 if the browser is unknown
	var uA = navigator.userAgent;
	var ibrowserType = -1;
	if (uA.indexOf("Opera") > -1) {
	  ibrowserType = 0;
	} else if (uA.indexOf("Safari") > -1) {
	  ibrowserType = 0;
	} else if (uA.indexOf("Konqueror") > -1) {
	  ibrowserType = 0;
	} else if (uA.indexOf("Gecko") > -1) {
	  ibrowserType = 0;
	} else if (uA.indexOf("MSIE") > -1) {
	  ibrowserType = 1;
	}
	return ibrowserType;
}


<!--<A HREF="javascript:popitup('model_images/m1.GIF',400,400)"><IMG SRC="model_images/m1.GIF" WIDTH="143" BORDER="0" HEIGHT="129" HSPACE="10" VSPACE="5" ALIGN=left></A>-->