function verify_login(form) {
	var msg;
	var empty_fields = "";
	var errors = "";

	required = new Array();
	required[0] = new Array("username", "Email", 0);
	required[1] = new Array("password", "Password", 0);

	for (i=0; i < required.length; i++) {
		var f = required[i][0];
		var l = required[i][1];
		var e = required[i][2];
		if (f == null) { continue; }
		var n = form[f]

		if ((n.type == "text") || (n.type == "textarea") || (n.type == "password")) {
			if ((n.value == null) || (n.value == "")) {
				empty_fields += "\n     " + l;
			}
		}
	}
	if (!empty_fields && !errors) {
		return true;
	} else {
	if (empty_fields) { // if there are errors or empty fields, print the alert.
		msg = "You are required to fill the following field(s): " + empty_fields + "\n";
		if (errors) msg += "\n"; }
		msg += errors;
		alert(msg);
		return false;
	}
}