Hey guys, I'm building an articles system that based on querystrings.
The system gets one value (Aid=number...), checks if it numeric or not null. But if the URL doesn't contain the Aid parameter, it generates an PHP error (page.php?Aid=1 >> page.php). How can I check if it's there?

Noam

I think you should use the empty function, which checks if a variable exists and also checks if it's not null.

if ($_GET["aid"]) {
// exists do something
} else {
// doesn't, do something else
}

Originally Posted by Insensus

I think you should use the empty function, which checks if a variable exists and also checks if it's not null.

It doesn't work because I'm basing the check through the QS (something like: isset($_GET['SearchInput']).

Originally Posted by chrishirst

if ($_GET["aid"]) {
// exists do something
} else {
// doesn't, do something else
}

Neither.

OK, you want my code :
the global function that checks the QS:
function QSfilterW($Qid)
{

if (trim($Qid)!="" || $Qid==false)
{
$Qid=trim($Qid);
$Qid=strip_tags($Qid);
return $Qid;
}
else
{
return false;
}

}

And the 'if':
if (QSfilterW($_GET['SearchInput'])==false || $_GET['SearchInput']!=true)
{...}

I'd say
if (trim($Qid)!="" || $Qid==false)
should be
if (trim($Qid)!="" && $Qid!=false)

well you right, it's logicly right, but still prints error:
Notice: Undefined index: SearchInput in C:\wamp\www\Yeadim\ArticleSearchINC.Do.php
which is: if (QSfilterW($_GET['SearchInput'])==false || $_GET['SearchInput']!=true)

That's just a notice, not even a warning.
It's something you can't get rid of, unless you put it inside a [b]try/catch[b] block.

PHP by default displays all errors except for notices, because you can mostly neglect them.
This function at the top of your script will do the same:

PHP Code:

error_reporting(E_ALL ^ E_NOTICE); 


this error means that the get request had no parameter ""SearchInput".
If you want to remove that notice, you should either check with isset in the if condifiotn, or initialize it before going in the if:

PHP Code:

$SearchInput=isset($_GET['SearchInput']?$_GET['SearchInput']:False
...
if (QSfilterW($SearchInput)==false || $SearchInput!=true){

} 


And note that it's just a notice, not an error.
It simply is mean as an informational message that PHP had to interpret what you wrote in a way that might not be the one you wanted.

like using $array[key] rather than $array['key']. In the first case, php tries to find a constant named "key", but as it doesn't finf one, fall back to look if the array have a key named "key".
You might had forgot to include the part who defined the constant.