function popup(pagina,nombre,ancho,alto){
	x= (screen.height-alto)/2;
	y= (screen.width-ancho)/2;
	eval("window.open('"+pagina+"','"+nombre+"','toolbar=no,location=no,directories=no,status=no,scrollbars=auto,resizable=no,copyhistory=no,width="+ancho+",height="+alto+",top="+x+",left="+y+"')");
}
function popup2(pagina,nombre,ancho,alto){
	x= (screen.height-alto)/2;
	y= (screen.width-ancho)/2;
	eval("window.open('"+pagina+"','"+nombre+"','toolbar=no,location=no,directories=no,status=yes,scrollbars=yes,resizable=yes,copyhistory=no,width="+ancho+",height="+alto+",top="+x+",left="+y+"')");
}

var doc=(document.all)? "document.all." : "document.";
	 var st=(document.all)? ".style.":".";
	 var ie=document.all
	 var stl=(ie)? ".style." : "." ;
	 var como=(ie)?	"pixelLeft" :"left" ;
	 var aba=(ie)? "pixelTop" : "top" ;