Checking if form element exist

Question

I save the form elements to a file and the following is working as expected.

$t_str .= "viewMandatory=".$_GET['viewMandatory'] ."\n";

But what I need is that if $_GET is set only then it should be appended to "t_str" string.

If no value for viewMandatory is received from the form, it should print nothing. How to add this check to the above statement?

There are [a lot](http://stackoverflow.com/questions/3496971/check-if-post-exists) of [similar](http://stackoverflow.com/questions/3432282/check-if-any-variables-are-passed-in-a-get) questions, and a [Google search is quite fruitful](http://www.google.co.uk/webhp?#hl=en&output=search&sclient=psy-.ab&q=check+if+get+variable+exists&fp=1). — Alex, Apr 09 '12 at 07:16

score 5 · Accepted Answer · edited Mar 18 '15 at 16:25

5

if (!empty($_GET['viewMandatory'])){
$t_str .= "viewMandatory=".$_GET['viewMandatory'] ."\n";
}

After 292 questions you should have encountered the empty() function.

edited Mar 18 '15 at 16:25

Sinister Beard

3,570
12
59
95

answered Apr 09 '12 at 07:11

i think you lack an enclosing `()` for the condition – Joseph Apr 09 '12 at 07:12

Mohammer · Answer 2 · 2012-04-09T08:05:25.160

$t_str .= (!empty($_GET['viewMandatory'])?$_GET['viewMandatory']:null;

This way you have less code, what makes it easier to read (at least to me, i love short forms), but the code will be executed everytime you request the page. that is not the case with Dragon's solution.

But think about code injection. Filter $_GET['viewMandatory'] the correctway before adding it to your string! Otherwise bad code can be injected quite easy, e.g.:

www.yourpage.com/page.php?viewMandatory=';BAD_CODE_HERE (or " instead of ')

score 1 · Answer 3 · answered Apr 09 '12 at 07:57

1

Use php isset    


if (isset($_GET['viewMandatory'])){
$t_str .= "viewMandatory=".$_GET['viewMandatory'] ."\n";
}

answered Apr 09 '12 at 07:57

Muhammad Raheel

19,823
7
67
103

Checking if form element exist

3 Answers3