HTML and PHP undefined index

Question

Here is the code, it is telling me I have an undefined index which is weird because I already defined it with HTML code. Any way around this error? or any ways to make it better would be much appreciated...

<h1>make a username</h1>
<form method="post" action="<?php echo  
htmlspecialchars($_SERVER["PHP_SELF"]); ?>"> 
Username: <input type="text" name="username" value="<?php echo $username; ?>">
<br><br>
<input type="submit" name="submit" value="Submit"> 
</form>

<?php 

$username = $_POST["username"];

echo $username;

?>

Use isset() and initialize the variable $username at start with empty value — Vaios P.
– Vaios P., Commented Apr 15, 2016 at 5:31

Asaph · Accepted Answer · 2016-04-15 05:26:08Z

1

$_POST["username"] will only be defined after you submit the form. When you first load the page (with an http GET), $_POST["username"] will be undefined.

answered Apr 15, 2016 at 5:26

Asaph

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Comments

Yash · Accepted Answer · 2016-04-15 05:26:58Z

0

After form submission it will work. You should try this:

<?php 
    if(isset($_POST["username"])){
        $username = $_POST["username"];
    }

?>

<h1>make a username</h1>
<form method="post" action="<?php echo  
htmlspecialchars($_SERVER["PHP_SELF"]); ?>"> 
Username: <input type="text" name="username" value="<?php echo (isset($username))? $username: ''; ?>">
<br><br>
<input type="submit" name="submit" value="Submit"> 
</form>

<?php
    echo (isset($username))? $username: '';
?>

answered Apr 15, 2016 at 5:26

Yash

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Comments

Zareef Ahmed · Accepted Answer · 2016-04-15 05:31:58Z

0

Do following changes to your code :

<h1>make a username</h1>
<form method="post" action="<?php echo  
htmlspecialchars($_SERVER["PHP_SELF"]); ?>"> 
Username: <input type="text" name="username" value="<?php echo $username; ?>">
<br><br>
<input type="submit" name="submit" value="Submit"> 
</form>

<?php 
/// This portion of code will execute only after you hit submit button
if(isset($_POST['username']))
{
$username = $_POST["username"];

echo $username;
}
?>

answered Apr 15, 2016 at 5:31

Zareef Ahmed

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Comments

Vantiya · Accepted Answer · 2016-04-15 05:46:18Z

0

if ( isset( $_POST["username"] ) ){

$username = $_POST["username"];

} else{

$username = '';

}
echo $username;

Try this code instead of your php code. This may help you.

answered Apr 15, 2016 at 5:46

Vantiya

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Comments

zzZZ · Accepted Answer · 2016-04-15 07:55:46Z

0

$_POST["username"]; add an @ before this,@$_POST['username'],'@' will ignore this error

answered Apr 15, 2016 at 7:55

zzZZ

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