Funcion que va entre <head> y </head>
Código PHP:
<script language="JavaScript" type="text/JavaScript">
<!--
function MM_openBrWindow(theURL,winName,features) { //v2.0
window.open(theURL,winName,features);
}
//-->
</script
>
y esto va en tu html
Código PHP:
<form name="form1" method="post" action="">
<input name="Submit" type="submit" onClick="MM_openBrWindow('ventana.htm','Popup','width=400,height=400')" value="Submit">
</form>
Saludos