var Wide = screen.width;

if (Wide <= 800)
{
	window.open("html/pop_up.htm","pop_up","status=yes,toolbar=no,resizable=no,scrollbars=yes,menubar=no,location=no,left=100,top=100,width=600,height=60");
}

else if (Wide >= 1024)
{
	window.open("html/pop_up.htm","pop_up","status=yes,toolbar=no,resizable=no,scrollbars=yes,menubar=no,location=no,left=100,top=100,width=600,height=150");
}


/*
window.open("html/pop_up.htm","pop_up","status=yes,toolbar=no,resizable=no,scrollbars=no,menubar=no,location=no,left=100,top=100,width=600,height=240");

width è costante, height varia...
height=320 per il carattere 'medio' con 1024x768 dpi
height=240 per il carattere 'medio' con  800x600 dpi
*/