modifying code to open popup

I had this function which opens a window in javascript

function windowopen(theURL,winSize) {
				if (winSize == 'page') 					{ myWidth=1000 ; myHeight=700 ; features = 'scrollbars=1, resizable=1, menubar=1' ; }
				else if (winSize == 'list') 			{ myWidth=700 ; myHeight=555 ; features = 'scrollbars=1, resizable=1, menubar=1' ; }
				else if (winSize == 'small') 			{ myWidth=400 ; myHeight=300 ; features = 'scrollbars=1, resizable=1, menubar=1' ; }
				else { myWidth=400 ; myHeight=500 ; features = 'scrollbars=0, resizable=0' ; }

				if(window.screen)
				{
					var myLeft = (screen.width-myWidth)/2;
					var myTop =  (screen.height-myHeight)/2;
					
					features+=(features!='')?',':''; 
					features+=',left='+myLeft+',top='+myTop; 
				}
				
				if (arguments[2]==null)
					window.open(theURL,'',features+((features!='')?',':'')+'width='+myWidth+',height='+myHeight); 
				else		
					window.open(theURL,arguments[2],features+((features!='')?',':'')+'width='+myWidth+',height='+myHeight); 
			}	

Select allOpen in new window

i want to convert into a jquery modal using colorbox which i can do

But here is a catch, i am opening one popup for captcha and once the captcha is ok, i want to the window closed and should trigger the above function to open popup window