Undefined index error PHP

Question

I\'m new in PHP and I\'m getting this error:

Notice: Undefined index: productid in /var/www/test/modifyform.php on line 32

Notice: Undef

Answer 1

This is happening because your PHP code is getting executed before the form gets posted.

To avoid this wrap your PHP code in following if statement and it will handle the rest no need to set if statements for each variables

       if(isset($_POST) && array_key_exists('name_of_your_submit_input',$_POST))
        {
             //process PHP Code
        }
        else
        {
             //do nothing
         }

Answer 2

Hey this is happening because u r trying to display value before assignnig it U just fill in the values and submit form it will display correct output Or u can write ur php code below form tags It ll run without any errors

Answer 3

There should be the problem, when you generate the <form>. I bet the variables $name, $price are NULL or empty string when you echo them into the value of the <input> field. Empty input fields are not sent by the browser, so $_POST will not have their keys.

Anyway, you can check that with isset().

Test variables with the following:

if(isset($_POST['key'])) ? $variable=$_POST['key'] : $variable=NULL

You better set it to NULL, because

NULL value represents a variable with no value.