function openWin(url,winname,w,h) {
 
topWin = (screen.availHeight - h) / 2;
leftWin = (screen.availWidth - w) / 2;
if (navigator.platform.indexOf('mac') != -1){
 props =  "menubar=yes,width="+w+",height="+h+",top="+topWin+",screenY="+topWin+",left="+leftWin+",screenX="+leftWin+",resizable=no"; }
else {
props = "width="+w+",height="+h+",top="+topWin+",screenY="+topWin+",left="+leftWin+",screenX="+leftWin+",resizable=no"; }
var myWin = window.open(url,winname,props);
myWin.focus();
return false;
}