Initializing Variables for PHP Script

petermcphee

I am just getting started with PHP, so apologies if this question is elementary.

I have an HTML page called "index.html", which has forms for user input. After the submit button is pressed, the information is passed to a php script called "output.php".

From this point, users can continue to use the forms on the "output.php" page and get new calculation results.

This is all good, but say a user sends the URL to a friend (or "output.php" is loaded first). The URL copied from the address bar will be domain.com/output.php.

When the user loads this page, a series of errors occurs because none of the user information is there.

Is there a way to avoid this?

In my HTML I have set default values for the form inputs, but these are overridden by the PHP script.

I have also tried initializing the variables like this:

$value1 = 10;

$value1 = $_REQUEST['formvalue1'];

So that if there is no form value, 10 will be used. But this doesn't work.

I also tried a conditional like:

If ($REQUEST['formvalue1'] = NULL) {
$value1 = 10; }
Else
{$value1 = $REQUEST['formvalue1'];}

But this didn't work either.

Has anybody else stumbled onto this and can shed some light?

Many thanks,

Peter.

jheitz

Try

If (isEmpty($_REQUEST['formvalue1']))

instead of

If ($_REQUEST['formvalue1'] = NULL)

petermcphee

Mmm, I tried this:

if (!empty($REQUEST['interest'])) {
$interest = 5 / 100; }
else {
$interest = $REQUEST['interest'] / 100; }

But it still won't pick up. Is this the standard proceedure though to initialize a PHP script?

laserlight

I think you reversed the logic. In this case, I suggest using [man]isset/man instead of empty() since zero is a valid value of interest.

if (!isset($_REQUEST['interest'])) {
	$interest = 5 / 100;
} else {
	$interest = $_REQUEST['interest'] / 100;
}

Houdini

Maybe if you showed what code you presently have someone here could more easily see just what is happening with your scripts. Show both the Form as well as the page you are using to process it with. When posting code please surround it with [ PHP ] your code in here and [ /PHP ] (without the spaces) Note you may also use [ HTML ] [ /HTML ] or [ CODE ] [ /CODE ] to enclose your code. Using the PHP the code is highlighted and will reveal some syntax errors not viewable unless presented in PHP BB Code tags.

petermcphee

Ah ha! That worked, thanks a lot laserlight.

I was thinking... would using include_once() also work here?

So, if the PHP page is loaded first, then use this code this time only?

laserlight

Off topic:

Houdini, if you want to post forum bbcode tags without actually having them evaluated, you can circumvent the parser by using bogus tags.

EDIT:
okay, so I cant seem to break the formatting of the breaking of the formatting.
Anyway, the technique I use involves an empty italic bbcode tag (i.e. open and close, nothing in between) just after the '['.

laserlight

I was thinking... would using include_once() also work here?

No, it would not. You have to use isset on empty to check that the given incoming variables actually exist.

Weedpacket

laserlight wrote:
Anyway, the technique I use involves an empty italic bbcode tag (i.e. open and close, nothing in between) just after the '['.

Or you can remember your numeric entities and write [php]...[/php] tags quite easily (you just have to remember that they're translated if you edit)