Notice: Undefined index: Notice

[lelyea]

I am in my 5th week of a PHP & MySQL class - no prior experience with either.

The relative code:

<form method="post" action="<? echo $_SERVER['PHP_SELF']; ?>?submit=true">

$submit = $_GET['submit']; <--- Notice on this line of code
if($submit == "true")
{

I kind of understand that I am getting this notice because ['submit'] is not
defined. I know that if I turn of 'notices' relative to coding standards the problem
kind of goes away (kind of because only on the server where I turn it off). It would be great if someone could help me with this problem and enlighten me on avoiding this problem with other types of variables and such.

Thanks

Len

[NogDog]

I'd probably do the following instead of assigning the $GET value to a new variable:

if(isset($_GET['submit']) and $_GET['submit'] == 'true')
{

PS: I should probably explain that in this case, because PHP evaluates the "and" condition from left to right, it only does the $_GET['submit'] == 'true' comparison if the isset($_GET['submit']) expression evaluates as true (since if it's false then the parser knows the whole "and" expression must be false, so it doesn't need to evaluate the second part). Therefore you avoid the invalid index notice if the variable is not set.