I'll post the code from techtuts, can't be bothered getting a better one for you. Analyse it and learn.
<?
ob_start();
include("config.php");
if ($logged[username])
{
// the user is logged in! We continue...
if (!$_POST[update])
{
// the form hasn't been submitted. We continue...
$profile = mysql_query("SELECT * from users where username = '$logged[username]'");
$profile = mysql_fetch_array($profile);
// the above lines get the information so that it can be displayed in the html form.
echo("
<center><form method=\"POST\">
<table width=\"100%\">
<tr>
<td align=\"right\" width=\"25%\">
Location
</td>
<td align=\"left\">
<input type=\"text\" size=\"25\" maxlength=\"25\" name=\"locate\" value=\"$profile[location]\"></td>
</tr>
<tr>
<td align=\"right\" width=\"25%\">
MSN Messenger
</td>
<td align=\"left\">
<input size=\"25\" name=\"msn\" value=\"$profile[msn]\"></td>
</tr>
<tr>
<td align=\"right\" width=\"25%\">
AOL Messenger</td>
<td align=\"left\">
<input size=\"25\" name=\"aim\" value=\"$profile[aim]\"></td>
</tr>
<tr>
<td align=\"right\" width=\"25%\">
Email Address</td>
<td align=\"left\">
<input size=\"25\" name=\"email\" value=\"$profile[email]\"></td>
</tr>
<tr>
<td align=\"center\">
</td>
<td align=\"left\">
<input type=\"submit\" name=\"update\" value=\"Update\"></td>
</tr>
</table>
</form>
</center>");
}
else
{
$email = htmlspecialchars($_POST[email]);
$aim = htmlspecialchars($_POST[aim]);
$msn = htmlspecialchars($_POST[msn]);
$locate = htmlspecialchars($_POST[locate]);
// the above lines get rid of all html.
echo ("Your profile has been updated!");
$update = mysql_query("Update users set email = '$email',
msn = '$msn', aim = '$aim', location = '$locate' where username = '$logged[username]'");
// updates the information in the database.
}
}
else
{
// They aren't logged in!
echo ("<a href=\"login.php\">You must login</a>");
}
?>