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===== Inner field calculation =====

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[[http://forum.phpwcms.org/viewtopic.php?p=111914#p111914]]


Re: Is there a way to calculate with form fields?

Posted by Oliver Georgi on Tue Dec 16, 2008 18:30 \\
A simple approach how to get this going is making use of (just an example):

a) 1 x hidden field (hidden_field_name) within your form -> this will be the target for your calculation and will be taken over into your mail form then.
b) additionally a frontend_init script "my_form_init.php":

<code php> if(isset($_POST['fieldname'])) {
  // hier die Berechnung durchführen - an der Stelle ganz beispielhaft realisiert.
  $_POST['hidden_field_name'] = xss_clean($_POST['fieldname']) * 1000;
}</code>

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===== Example 01 =====

> I'm setting up a site for a customer who will add a lot of articles describing different products. I don't want him(my customer) to set up a form for every product. 
> I want to "call" a form from the template with some sort of identification of the current article. 
>
> This is described also a thousand times inside the forum - working like "send a friend".
> Use an article with content part based on your needs outside public access.
> Then use {SHOW_CONTENT:CP,ID} (ID = ID of the content part form) inside of your template.
> It's no "out of the box" solution - but as I said it is discussed somewhere here in the forum. 

==== Finish ====
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> Create the file ##/template/inc_script/frontend_init/check.php##
<code php>
<?php
if(isset($_POST['eingabe'])) {
  // do your calculation here - this is an example.
  $_POST['versteckt'] = xss_clean($_POST['eingabe']) * 1000;
}
?>
</code>
> Now you can do your calculations. 
> In our example the field input is multiplied by 1000, while the output is showing the input value and the result.
> 
> Insert a default for the hidden field (hidden). Define this field as "required". 
> //(If an error is encountered, set the field value to "" ($_POST['my_hidden_field'] = "";) ).// 
> 
> Result: Error -> if the value is validating, then the hidden field value will too contain the valid result.