PHP Undefined Index [duplicate]

Question

This is going to sound really stupid, but I cannot figure out why I am getting this error.

I have created a selection box, named "query_age" in my html form:

<form method="get" action="user_list.php"> <select name="query_age">   <option value="">Doesn't matter</option>   <option value="between 18 and 30">18 - 30</option>   <option value="between 31 and 40">31 - 40</option>   <option value="between 41 and 50">41 - 50</option>   <option value="between 51 and 60">51 - 60</option>   <option value="between 61 and 70">61 - 70</option>   <option value="between 71 and 80">71 - 80</option>   <option value="between 81 and 90">81 - 90</option>   <option value="> 90">Older than 90</option> </select> 

In the corresponding php form, I have:

$query_age = $_GET['query_age']; 

When I run the page, I get this error:

Notice: Undefined index: query_age in index.php on line 19

I don't understand why this is happening, and I'd love to know how to make it go away.

Answer 1

I don't see php file, but that could be that -
replace in your php file:

$query_age = $_GET['query_age']; 

with:

$query_age = (isset($_GET['query_age']) ? $_GET['query_age'] : null); 

Most probably, at first time you running your script without ?query_age=[something] and $_GET has no key like query_age.