Incorrect PHP code is working, shoud I "fix" it?

rblampain · 04-28-2006, 03:22 AM

I have the following line of HTML code:
<input type='hidden' name='flag' vflag='0'></form>
I meant to type "value='0'" instead of "vflag='0'" but it works despite my basic knowledge telling me it's incorrect code.
It works because the statements included in the following are all executed by PHP:
if(isset($_POST['flag']) && ($_POST['vflag']==0)) {
some code ;
$vflag+=1;
}

Should I "fix" it?

Thank you for your help.

Nathanael · 04-28-2006, 04:12 AM

sure it works...
<input type='hidden' name='flag' vflag='0'>
would set $_POST['flag'] with no value, so
isset($_POST['flag']) will return true.
$_POST['vflag'] is not set, therfore equals to 0
to set $_POST['vflag'] = 0 you would want
<input type='hidden' name='flag' value='0'>
<input type='hidden' name='vflag' value='0'>

on top of that, you should fix it, as it is not valid xhtml, or html.

Spudley · 04-28-2006, 08:49 AM

Short answer: Yes. If you spot a coding bug, and you know how to fix it, you should do so. What possible reason could you have for not fixing it?

Also the PHP code seems to be confusing the field name too:

Code:

if(isset($_POST['flag']) && ($_POST['vflag']==0)) {

Is the field supposed to be called 'flag' or 'vflag'? Assuming they're both supposed to be referencing the same field, you should correct that as well as the html.

rblampain · 04-28-2006, 12:10 PM

Thank you both. What i found confusing was that "vflag" not set did not return a value of 0 but a value of "".

Hko · 04-28-2006, 04:13 PM

$_POST['vflag'] does not exist obviously, so an empty string ( "" ) is the value of $_POST['vflag']. If you then use it as an integer, it will be converted automatically to an integer of zero.

taylor_venable · 04-28-2006, 09:28 PM

To differentiate between "" and 0, use the triple-equals === for equality checks. This ensures that the types between the two operands are consistent, not merely equivalent in the course of evaluation. Example:

Code:

"" == 0 // returns true
"" === 0 // returns false

Also, whenever you find a bug, you should fix it. This practice improves not only maintainability, but also security. All security flaws are bugs, therefore less bugs means less security vulnerabilities.

rblampain · 04-28-2006, 10:33 PM

Thank you all again, it's all valuable info.