View difference between Paste ID: iFZKhM6B and LyKCMYbB

 <?php
 // http://www.gravityhelp.com/forums/topic/custom-input-mask-for-a-valid-url#post-157749
-// change the 338 to your form ID
+// revised to handle multiple forms and their associated URL fields
-add_filter('gform_pre_submission_filter_338', 'force_http');
+add_filter('gform_pre_submission_filter_338', 'force_http_prefix');
-function force_http($form) {
+function force_http_prefix($form) {
     $formfields = array(
-        // change the 3 to your field ID where the URL will be entered
+        // add all your form IDs here with their corresponding field ID
-        // change it a few lines further down as well
+        // for example, this will look for field 3 in form 338
-        // trim the whitespace first, then make it lowercase
+        '338' => '3',
-        $haystack = strtolower(trim($_POST['input_3']));
+        '12' => '3',
         '2' => '10',
         '8' => '7'
         // for all 11 forms ...
         );
 
-        if (substr($haystack, 0, 7) == $needle) {
+    // see if the form ID is one of the keys in our array
-                return $form;
+    // if so, then run the code to check the appropriate field
     if (array_key_exists($form['id'], $formfields)) {
-        else {
+
-                $_POST['input_3'] = $needle . $haystack;
+        // create a variable for the input we want to modify for this form
-                return $form;
+        $input_id = 'input_' . $formfields[$form['id']];
         $haystack = strtolower(trim($_POST[$input_id]));
 
         // check for http:// at the beginning of the string
         $needle = 'http://';
 
         // if the http:// is not at the beginning of the string, add it and modify the POST value
         if (substr($haystack, 0, 7) <> $needle) {
             $_POST[$input_id] = $needle . $haystack;
         }
     }
     // return the form either way
     return $form;
 }