HELP a beginner... simple question!

I am trying to create a very simple php application that calculates TWO percentages from FOUR input fields.

It's really simple, I know, but I have this big new php manual, and I can't find what I am doing wrong.

My total experience with php is about 6 hours... I am a real green noob.

This is the page:
Resizing calculator

Thanks!

 

Without seeing code we can't help.

 

<form method=get action=<?php print $PHP_SELF; ?>> 
Original pattern width: <input type=text name=owidth /><br>
Original pattern height: <input type=text name=oheight /><br>
Desired pattern width: <input type=text name=dwidth /><br>
Desired pattern height: <input type=text name=dheight /><br>
<p align="center">
<font size=3 color="#EEE9BF">
<input type=submit name=submit value=Calculate style="border: 1px solid black; background-color: #B7C99C; color: #FFFFFF">  
</p></form>


		<?php
                {
		$result1 =$owidth / $dwidth *100;
		echo "Multiply the width by: $result1";
		}

                {
		$result2 =$owidth / $dwidth *100;
		echo "Multiply the height by: $result2";
		}
		
		?>

PHP:

 

I should probably be very embarassed... I am sure my errors are obvious!

 

<?php

$result1 =(($owidth / $dwidth) *100);
echo "Multiply the width by: $result1";

$result2 =(($owidth / $dwidth)*100);
echo "Multiply the height by: $result2";


?>

Code (markup):

Try that not tested though

 

Big G, I uploaded it... not working!

 

First off, you should really do like name="dwidth"

Secondly, when fetching the form you should really use $_GET['dwith'] and not rely on global vars.

Thirdly, even though it matters less here, you should really sanitize your form input. So make sure dwith etc. is as expected, a number.

Finally, add some error reporting. The PHP error says division by zero, indicating dwith = 0 or not set at all.

Do stuff like, if(!is_numeric($_GET['dwidth'])) { echo 'error! not numeric!'; }

Have a look what actually comes through the form before trying to fix it, so echo $_GET['dwidth'] etc. between big fat <h1>'s so it's blatantly obvious what's going on.

 

TOPS30, thank you.

I've done and uploadded a version with names in quotation marks.

As for the $_GET, I looked it up and found this.

I would prefer that the name of variables etc. don't show up in the URL. Though, being a complete and utter newborn beginner, I would be elated if I only got it to work.

Amazingly I understand the last part of your post " if(!is_numeric($_GET['dwidth'])) { echo 'error! not numeric!'; }" and I will try to implement such functions once I've got the basic operation working.

Still not working, so I guess it wasn't the quotation marks.

 

You specifically made the form method="GET" hence retrieving the data via $_GET. You can change it to POST if you want. It then becomes $_POST['dwidth'].

Show us your cleaned up code.

When you paste chunks of PHP here, use [php]code here[/php]

 

<form method="post" action=<?php print $PHP_SELF; ?>> 
Original pattern width: <input type="text" name="owidth" /><br>
Original pattern height: <input type="text" name="oheight" /><br>
Desired pattern width: <input type="text" name="dwidth" /><br>
Desired pattern height: <input type="text" name="dheight" /><br>
<p align="center">
<font size=3 color="#EEE9BF">
<input type=submit name=submit value=Calculate style="border: 1px solid black; background-color: #B7C99C; color: #FFFFFF">  
</p></form>


<?php
$result1 =(($owidth / $dwidth) *100);
echo "Multiply the width by: $result1";

$result2 =(($owidth / $dwidth)*100);
echo "Multiply the height by: $result2";
?>

PHP:

 

<form method="post" action=<?php print $PHP_SELF; ?>> 
Original pattern width: <input type="text" name="owidth" /><br>
Original pattern height: <input type="text" name="oheight" /><br>
Desired pattern width: <input type="text" name="dwidth" /><br>
Desired pattern height: <input type="text" name="dheight" /><br>
<p align="center">
<font size=3 color="#EEE9BF">
<input type=submit name=submit value=Calculate style="border: 1px solid black; background-color: #B7C99C; color: #FFFFFF">  
</p></form>


<?php
if (isset($submit)) { //so it doesn't load if not submitted
$result1 =(($_POST['owidth'] / $_POST['dwidth']) * 100);
echo "Multiply the width by:" . $result1;

$result2 =(($_POST['owidth'] / $_POST['dwidth']) * 100);
echo "Multiply the height by:" . $result2;
}?>

PHP:

Try that and paste any errors, if any.

BTW result1 and 2 will be the exact same, so a lot of the code is rather pointless...

 

This gives a "parsing error."

I did correct the formula a bit:

<?phpif (isset($submit)) 
{ //so it doesn't load if not submitted$result1 =(($_POST['owidth'] / $_POST['dwidth']) * 100);
echo "Multiply the width by:" . $result1; $result2 =(($_POST['owidth'] / $_POST['dwidth']) * 100);
echo "Multiply the height by:" . $result2;}?>

PHP:

 

<form method="post" action=<?php print $PHP_SELF; ?>> 
Original pattern width: <input type="text" name="owidth" /><br>
Original pattern height: <input type="text" name="oheight" /><br>
Desired pattern width: <input type="text" name="dwidth" /><br>
Desired pattern height: <input type="text" name="dheight" /><br>
<p align="center">
<font size=3 color="#EEE9BF">
<input type=submit name=submit value=Calculate style="border: 1px solid black; background-color: #B7C99C; color: #FFFFFF">  
</p></form>


<?php

if($submit)
{

$result1 =(($_POST['owidth']/ $_POST['owidth']) *100);
echo "Multiply the width by: $result1 <br />";

$result2 =(($_POST['dwidth']/ $_POST['dwidth']) *100);
echo "Multiply the height by: $result2";

}
?>

PHP:

Should work

 

If there's a parsing error, please show us and the corresponding line.

 

Gekkie's code doesn't give a parsing error.

However, upon "submit" the page reloads and no solutions are given to the calculations.

 

Within the if($submit) add some debugging like:

echo '<h2>Dwidth:' . $_POST['dwidth'] . '</h2>';

PHP:

And then see whether that shows. That way you can reverse debug, bottom up, your code.

I'd also make it type="submit" name="submit". With neat "s.

 

$result1 =(($_POST['owidth']/ $_POST['owidth']) *100);
echo "Multiply the width by: $result1 <br />";

$result2 =(($_POST['dwidth']/ $_POST['dwidth']) *100);
echo "Multiply the height by: $result2";

PHP:

Stupid me i divide owidth with owidth you should replace does words with the ones you wanna divide.

 

I found the problem... Look at the page source, $PHP_SELF isn't actually put in the form.

Make it

<form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>"> 

PHP:

 

Yes, I changed it to:

<?php if($submit)
{
$result1 =(($_POST['owidth']/ $_POST['dwidth']) *100);
echo "Multiply the width by: $result1 <br />";
$result2 =(($_POST['oheight']/ $_POST['dheight']) *100);
echo "Multiply the height by: $result2";
}?> 

PHP:

Still not calculating...

 

Also replace the if ($submit with this:

if($_POST["submit"]){

To be sure. Some server don't have global vars enabled.