Variables not working within Functions

["Adam Symonds" <adamsymonds@froggy.com.au>]

Hi,
I am starting to us functions with my work but I am having troubles
With the variables in the functions..

If I have the following function called from my page it will work but the
variable won?t
($username)
but if I put this code straight on the page then it works fine..

Any reason for the variable not to work in the function but in straight
coding?
Thanx



Sample Function Below:

======================================
function LoginSystem()
 {
echo "<div align=right>";
if ( !isset( $_SESSION['login'] ) ) {

echo "<form action=../Users/Login.php method=post>";
echo "<font size=1>Username: </font><input name=user type=text
size=10>&nbsp;<font size=1>Password: </font><input name=pass type=password
size=10>&nbsp;<input type=submit value=GO><br>";
echo "<a href=../Register.php><font size=1>Not A Member
Yet?</font></font></a>&nbsp;";
echo "</form>";

 } else {
echo "<font size=1>Welcome $username &nbsp;&nbsp;&nbsp;<a
href=../Users/Logout.php><font
size=1>Logout</a>&nbsp;&nbsp;&nbsp;</font></font><br><br>";
}
echo "</div>";
 }