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php, how to catch if a variable is never sent (post or get)

Posted: Wed Apr 04, 2007 1:31 pm
by RICKYJ
Hi,

I'm running into something that seems quite trivial. I'm primarily a java programmer, but am creating a web site that has a bit of php code.

The problem is, I have created a search page in php that querries a db, and returns to self with the results.

One of the problems im having is that if a user goes directly to search php, then there is an error thrown because there is no variable sent to this page.

I need a way of "catching" this error without having to define.

I have tried something like:

Code: Select all

if(  $_POST['myVar'] == NULL ){
$variableDefinedfromMyVar = "no search submited";
}
// problem is "$_POST['myVar']" thows an error since myVar is undefined

I also need to catch other nonsubmitted variables but cant see how ???? any suggestions :)

Posted: Wed Apr 04, 2007 1:38 pm
by Chris Corbyn
isset().

Posted: Wed Apr 04, 2007 1:46 pm
by RICKYJ
wow you're fast, looking into it on the php manual now, thanks

Posted: Wed Apr 04, 2007 1:55 pm
by RICKYJ
ok so it looks like I can just use:

Code: Select all

If ( isset($_POST['myVar']) == TRUE) {
// var has been initialised
} else {// not initialised yet}
Cheers ears

Posted: Wed Apr 04, 2007 3:29 pm
by RobertGonzalez
Nope, you can get away with just isset()

Code: Select all

<?php
if (isset($_POST['myvar']))
{
    // Execute if set
}
?>