undefined value when checkbox is unchecked php

Question

I have this registration code. I want people to decide if they want to be added to an email listserv or not. The code executes appropriately when the box is checked but I get:

Notice: Undefined index: maillist in C:\xampp\htdocs\website\register.php on line 21

when the box is unchecked. Below is the code. I'm not great at programming so please pretend like I'm stupid when responding. Thanks.

    <tr><td>Add me to your listserve:</td><td><input type="checkbox" name="maillist">  </td></tr>

    $name=mysql_real_escape_string($_POST['name']);
    $dob=mysql_real_escape_string($_POST['dob']);
    $loginid=mysql_real_escape_string($_POST['loginid']);
    $password=mysql_real_escape_string($_POST['password']);
    $emailaddress=mysql_real_escape_string($_POST['emailaddress']);
    $description=mysql_real_escape_string($_POST['description']);
    $maillist=$_POST['maillist'];

    mysql_query("INSERT INTO demographics    values('$name','$dob','$loginid','$password','$description')") or DIE(mysql_error());

    if($maillist==true){
      mysql_query("INSERT INTO maillist values('$name','$emailaddress')") or DIE(mysql_error());
    }

If the checkbox is unchecked the no value will be sent through the form so you can do something like: `$maillist = isset($_POST['maillist']);` — Cyclonecode, Dec 08 '13 at 04:13
Please [use the search](http://stackoverflow.com/search?q=%5Bphp%5D+Undefined+index) before asking a question. This problem has been answered several thousand times before. — Sverri M. Olsen, Dec 08 '13 at 04:20

score 3 · Accepted Answer · answered Dec 08 '13 at 04:13

3

HTML forms don't create a POST variable for unchecked checkboxes. You need to check if the variable exists to know if it's checked or not:

$maillist = isset($_POST['maillist']);

answered Dec 08 '13 at 04:13

bchociej

1,369
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score 0 · Answer 2 · answered Dec 08 '13 at 04:13

0

If your checkbox is unchecked the maillist will be not set. Check $_POST['maillist'] before using it whether is comes in post array.

$maillist=isset($_POST['maillist']) ? $_POST['maillist'] : '';

answered Dec 08 '13 at 04:13

Roopendra

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I see. Thanks for the help. Also, I tried to search for the answer but couldn't find it. I'll try harder next time. – user3079087 Dec 08 '13 at 19:34

score 0 · Answer 3 · answered Dec 08 '13 at 04:29

0

You have to check if the variable is set:

<input type="checkbox" name="maillist" value= true>

if(isset($_REQUEST['maillist']) {
....
}

answered Dec 08 '13 at 04:29

Fabrizio Mazzoni

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undefined value when checkbox is unchecked php

3 Answers3