function openwindow(url){
 var v = window.open (url,'mywindow','scrollbars,menubar=1,top = 10,left=50,resizable=1,width=800,height=600');
 v.focus();
}

function openwindowP(url,w,h){
    var left = (screen.width - w) / 2;
    var top = (screen.height - h) / 2;
 
 var v = window.open (url,'mywindow','scrollbars=auto,menubar=0,top = '+top+',left='+left+',resizable=1,width='+w+',height='+h);
 v.focus();
}