function makeWindow(URL) {
popX=400
popY=300
posX=((screen.availWidth/2)-(popX/2))
posY=((screen.availHeight/2)-(popX/2))
window.open(URL,"Pagename","height=500,width=450,toolbar=0,menubar=0,directories=0,scrollbars=1,left="+posX+",top="+posY);
}