Question

I am developing login form In PHP
The form is as follows

<form method="post" action="Login.php" id="Log">
<select id="Login" name="Type">
<option value="Sel" selected="selected">Select Login type</option>
<option value="Student">Student</option>
<option value="Faculity">Faculity</option>
</select>
<div id="type">
<p id="Ch">Group Id: &nbsp;<input id="l" name="log" type="text"/></p>
<p id="Pass">Password: &nbsp; <input id="p" name="Pass" type="password" /></p>
<input id="Cond" type="Text" />
<input type="submit" value="Login"  />
<p id="Invalid" style="padding-top:.75em; color:#FF0000;">Invalid Login Or Password</p>
</form>

In post.php I connect with database and check login and passwords.

I want to show the <p id="invalid"> tag when password or login don’t match in the same form below it without any delay.

The <p id="invalid"> is hidden at the beginning and only be shown when login or pasword is incorrect

How can I achieve this/ connect with database through PHP?

Answer 1

I agree with Galen’s answer. You should put the login procession stuff on the same page. If you don’t know how to do that, you should do this:

<?php
$itswrong = false;
if (isset($_POST['Pass']) && isset($_POST['log'])) {
$sql = 'SELECT * FROM your_database_name WHERE group_id = '{$_POST['log']}' AND password = SHA1('{$_POST['Pass']}')";
$result = @mysql_query($sql) or die (mysql_error());
if (mysql_num_rows($result) == 1) {
// Match was found!
// Do whatever here, e.g. session registering (starting a session), etc.
} else {
// Oh damn, it's wrong!
$itswrong = true;
// Do stuff here
}
} else {
// Move your form in here
}
?>

All you need to do in your form is move it to under // Move your form in here, change
this:

<p id="Invalid" style="padding-top:.75em; color:#FF0000;">Invalid Login Or Password</p>

to this:

<?php
if (isset($_POST['Pass']) && isset($_POST['log']) && $itswrong == true) {
?>
<p id="Invalid" style="padding-top:.75em; color:#FF0000;">Invalid Login Or Password</p>
<?php
}
?>

and also change the values in the SQL query to suit your needs. Then it would work. I want you to move the form under // Move your form in here, because then if the form is not submitted, it will show.

EDIT: Also change the title of your form,

From this:

<form method="post" action="Login.php" id="Log">

To this:

<form method="post" action="<?php echo $_SERVER['REQUEST_URI']; ?>" id="Log">

That will make the page just post the data to itself, making my code on top possible.

I do not suggest ajax, as it is WAY harder for hackers to hack into PHP then JavaScript-related technology, as JavaScript is client-side and PHP is server-side.

Please notify me if you still have problems.

Lucas