function popUp(myPage, myWidth, myHeight)  
{ 
LeftPosition= (screen.width *0.5)-(myWidth*0.5);
TopPosition=(screen.height *0.5)-(myHeight*0.5);                   
             window.open(myPage, 'hello','width='+myWidth+',height='+myHeight+',top='+TopPosition+',left='+LeftPosition+',scrollbars=no,location=no,directories=no,status=no,menubar=no,toolbar=no,resizable=no');           
}