Remove attribute if it has no value and readd it with a null value, fixes #108 (#115)

Author: k1sul1

classes/class-cpt-wplf-form.php

@@ -939,11 +939,19 @@ public function shortcode( $shortcode_atts, $content = null ) {
     // we don't render id and class as <form> attributes
     $id = $attributes['id'];
     $xclass = $attributes['xclass'];
+
     $attributes = array_diff_key( $shortcode_atts, array(
       'id' => null,
       'xclass' => null,
     ) );
 
+    foreach ( $attributes as $k => $v ) {
+      if ( is_numeric( $k ) ) {
+        unset( $attributes[ $k ] );
+        $attributes[ $v ] = null; // empty value
+      }
+    }
+
     // display form
     return $this->wplf_form( $id, $content, $xclass, $attributes );
   }