https://www.machform.com/forums/ MachForm Community Forums Topic: HOW TO: Add Mod-10 Credit Card validation to your form. en Mon, 04 May 2026 00:28:58 +0000 https://www.machform.com/forums/topic/how-to-add-mod-10-credit-card-validation-to-your-form#post-21000 Fri, 09 May 2014 21:59:56 +0000 aolmos 21000@https://www.machform.com/forums/ <p>What about version 4? </p> https://www.machform.com/forums/topic/how-to-add-mod-10-credit-card-validation-to-your-form#post-16815 Thu, 17 Jan 2013 04:34:29 +0000 tmparisi 16815@https://www.machform.com/forums/ <p>Hi aolmos, unfortunately I cannot help you with this. I have never used v2. Best of luck! </p> https://www.machform.com/forums/topic/how-to-add-mod-10-credit-card-validation-to-your-form#post-16103 Mon, 01 Oct 2012 17:00:49 +0000 aolmos 16103@https://www.machform.com/forums/ <p>How can I include this code in machform 2? We have customized our machform and we can't switch to machform 3 </p> https://www.machform.com/forums/topic/how-to-add-mod-10-credit-card-validation-to-your-form#post-14611 Mon, 07 May 2012 11:47:45 +0000 yuniar 14611@https://www.machform.com/forums/ <p>Thank you for sharing this! </p> https://www.machform.com/forums/topic/how-to-add-mod-10-credit-card-validation-to-your-form#post-14608 Mon, 07 May 2012 06:39:31 +0000 tmparisi 14608@https://www.machform.com/forums/ <p>For those of you that take credit card numbers in your forms, here is a simple way to set up CC validation in your form that ultimately checks for several factors including, length, prefix, and mod-10 algorithm. The following code is adapted from: <a href="http://www.braemoor.co.uk/software/creditcard.php" rel="nofollow">http://www.braemoor.co.uk/software/creditcard.php</a></p> <p>Open up your post_functions.php file in your include folder and find the following lines of code:</p> <pre><code>if(!empty($row[&#39;form_redirect_enable&#39;])){ $form_redirect = $row[&#39;form_redirect&#39;]; }</code></pre> <p>Right below this code, add the following verification script:</p> <pre><code>//custom code //====================START CC Validation======================= if ($form_id == 15 || $form_id == 3 || $form_id == 4 || $form_id == 10 || $form_id == 11) { //form numbers that have text fields that you want to perform CC validation if($form_id == 15) //if form #15, set the credit card type dropdown and the credit card number fields according to the element numbers for that form { $cc_validate_id = 1; //set credit card number field $cc_validate_type = 2; //set credit card type field } if($form_id == 3) { $cc_validate_id = 28; $cc_validate_type = 17; } if($form_id == 4) { $cc_validate_id = 29; $cc_validate_type = 17; } if($form_id == 10) { $cc_validate_id = 28; $cc_validate_type = 17; } if($form_id == 11) { $cc_validate_id = 29; $cc_validate_type = 17; } $failcheck = 0; if (!empty($table_data[&#39;element_&#39; . $cc_validate_id])) { if($table_data[&#39;element_&#39; . $cc_validate_type] == 1) //check if credit card dropdown type is 1 { $cardname = &#39;american express&#39;; //if so, set $cardname equal to american express } else if($table_data[&#39;element_&#39; . $cc_validate_type] == 2) { $cardname = &#39;visa&#39;; } else if($table_data[&#39;element_&#39; . $cc_validate_type] == 3) { $cardname = &#39;mastercard&#39;; } else if($table_data[&#39;element_&#39; . $cc_validate_type] == 4) { $cardname = &#39;discover&#39;; } else { $cardname = &#39;&#39;; } $cardnumber = $table_data[&#39;element_&#39; . $cc_validate_id]; //set $cardnumber equal to the credit card number entered by user $cards = array ( array (&#39;name&#39; =&gt; &#39;American Express&#39;, &#39;length&#39; =&gt; &#39;15&#39;, &#39;prefixes&#39; =&gt; &#39;34,37&#39;, &#39;checkdigit&#39; =&gt; true ), array (&#39;name&#39; =&gt; &#39;Discover&#39;, &#39;length&#39; =&gt; &#39;16&#39;, &#39;prefixes&#39; =&gt; &#39;6011,622,64,65&#39;, &#39;checkdigit&#39; =&gt; true ), array (&#39;name&#39; =&gt; &#39;MasterCard&#39;, &#39;length&#39; =&gt; &#39;16&#39;, &#39;prefixes&#39; =&gt; &#39;51,52,53,54,55&#39;, &#39;checkdigit&#39; =&gt; true ), array (&#39;name&#39; =&gt; &#39;VISA&#39;, &#39;length&#39; =&gt; &#39;16&#39;, &#39;prefixes&#39; =&gt; &#39;4&#39;, &#39;checkdigit&#39; =&gt; true ), array (&#39;name&#39; =&gt; &#39;VISA Electron&#39;, &#39;length&#39; =&gt; &#39;16&#39;, &#39;prefixes&#39; =&gt; &#39;417500,4917,4913,4508,4844&#39;, &#39;checkdigit&#39; =&gt; true ) ); $ccErrorNo = 0; $ccErrors [0] = &quot;Unknown card type&quot;; $ccErrors [1] = &quot;No card number provided&quot;; $ccErrors [2] = &quot;Credit card number has invalid format&quot;; $ccErrors [3] = &quot;Credit card number is invalid&quot;; $ccErrors [4] = &quot;Credit card number is wrong length&quot;; // Establish card type $cardType = -1; for ($i=0; $i&lt;sizeof($cards); $i++) { // See if it is this card (ignoring the case of the string) if (strtolower($cardname) == strtolower($cards[$i][&#39;name&#39;])) { $cardType = $i; break; } } // If card type not found, report an error if ($cardType == -1 &#38;&#38; $failcheck == 0) { $errornumber = 0; $errortext = $ccErrors [$errornumber]; $error_elements[$cc_validate_id] = $ccErrors [$errornumber]; $failcheck = 1; } // Ensure that the user has provided a credit card number if (strlen($cardnumber) == 0 &#38;&#38; $failcheck == 0) { $errornumber = 1; $errortext = $ccErrors [$errornumber]; $error_elements[$cc_validate_id] = $ccErrors [$errornumber]; $failcheck = 1; } // Remove any spaces from the credit card number $cardNo = str_replace (&#39; &#39;, &#39;&#39;, $cardnumber); // Check that the number is numeric and of the right sort of length. if (!preg_match(&quot;/^[0-9]{13,19}$/&quot;,$cardNo) &#38;&#38; $failcheck == 0) { $errornumber = 2; $errortext = $ccErrors [$errornumber]; $error_elements[$cc_validate_id] = $ccErrors [$errornumber]; $failcheck = 2; } // Now check the modulus 10 check digit - if required if ($cards[$cardType][&#39;checkdigit&#39;] &#38;&#38; $failcheck == 0) { $checksum = 0; // running checksum total $mychar = &quot;&quot;; // next char to process $j = 1; // takes value of 1 or 2 // Process each digit one by one starting at the right for ($i = strlen($cardNo) - 1; $i &gt;= 0; $i--) { // Extract the next digit and multiply by 1 or 2 on alternative digits. $calc = $cardNo{$i} * $j; // If the result is in two digits add 1 to the checksum total if ($calc &gt; 9) { $checksum = $checksum + 1; $calc = $calc - 10; } // Add the units element to the checksum total $checksum = $checksum + $calc; // Switch the value of j if ($j ==1) {$j = 2;} else {$j = 1;}; } // All done - if checksum is divisible by 10, it is a valid modulus 10. // If not, report an error. if ($checksum % 10 != 0 &#38;&#38; $failcheck == 0) { $errornumber = 3; $errortext = $ccErrors [$errornumber]; $error_elements[$cc_validate_id] = $ccErrors [$errornumber]; $failcheck = 3; } } // The following are the card-specific checks we undertake. // Load an array with the valid prefixes for this card $prefix = explode(&#39;,&#39;,$cards[$cardType][&#39;prefixes&#39;]); // Now see if any of them match what we have in the card number $PrefixValid = false; for ($i=0; $i&lt;sizeof($prefix); $i++) { $exp = &#39;/^&#39; . $prefix[$i] . &#39;/&#39;; if (preg_match($exp,$cardNo)) { $PrefixValid = true; break; } } // If it isn&#39;t a valid prefix there&#39;s no point at looking at the length if (!$PrefixValid &#38;&#38; $failcheck == 0) { $errornumber = 3; $errortext = $ccErrors [$errornumber]; $error_elements[$cc_validate_id] = $ccErrors [$errornumber]; $failcheck = 3; } // See if the length is valid for this card $LengthValid = false; $lengths = explode(&#39;,&#39;,$cards[$cardType][&#39;length&#39;]); for ($j=0; $j&lt;sizeof($lengths); $j++) { if (strlen($cardNo) == $lengths[$j]) { $LengthValid = true; break; } } // See if all is OK by seeing if the length was valid. if (!$LengthValid &#38;&#38; $failcheck == 0) { $errornumber = 4; $errortext = $ccErrors [$errornumber]; $error_elements[$cc_validate_id] = $ccErrors [$errornumber]; $failcheck = 4; }; } } //====================END CC Validation=======================</code></pre> <p>This is probably not perfect nor is it most likely the most efficient method, but it is tested and does work. I hope it can be of some use for others out there! </p>