EM Pro Forms max_input_vars fix

<?php
/*
Plugin Name: Events Manager Pro Forms Fix
Version: 1.2
Plugin URI: http://wp-events-plugin.com
Description: Fixes php.ini max_input_vars limitation on 24+ form fields for EM Form Builder
Author: Marcus Sykes
Author URI: http://wp-events-plugin.com
*/
/*
 fixing max_input_vars = 1000 limit which is preventing more than 23 custom fields
data package coming in as json string in 'fields_json'
stripcslashes()
*/
class EMP_Forms_Fix{
    public static function init(){
        global $pagenow;
        if( !empty($_REQUEST['page']) && $_REQUEST['page'] == 'events-manager-forms-editor'){
            add_action('admin_init', 'EMP_Forms_Fix::post', 8, 1);
            add_action('admin_head', 'EMP_Forms_Fix::js', 10, 1);
        }
    }

    public static function post(){
        if( isset($_REQUEST['fields_json']) ){
            $str = $test = str_replace(array('[]\\"','\\"', "\\'",'\\\\'),array('"','"',"'",'\\'), trim($_REQUEST['fields_json']));
            $test = (array) json_decode($test);
            if (count($test)) $_REQUEST = array_merge($_REQUEST, $test);
        }
    }

    public static function js( $form_name) {
        ?>
        <script type="text/javascript">
            jQuery(document).ready( function($){
                if (typeof JSON.stringify != 'undefined'){
                    if (typeof jQuery.serializeJSON == 'undefined') jQuery.fn.serializeJSON = function(){
                        var o = {},
                        a = this.serializeArray();
                        jQuery.each(a, function() {
                            if (o[this.name] !== undefined) {
                                if (!o[this.name].push) { o[this.name] = [o[this.name]]; }
                                o[this.name].push(this.value || '');
                            } else {
                                o[this.name] = this.value || '';
                            }
                        });
                        return JSON.stringify(o, null, 2);
                    }

                    jQuery('.em-form-custom').submit(function(event){
                        var myform = jQuery(this);
                        if (myform.find('#fields_json').length) return; //have already made switch, so let default submit take place
                        event.preventDefault();
                        var data = myform.serializeJSON();
                        myform.empty().append(jQuery('<input/>').attr({id:'fields_json', name:'fields_json', value:data})).submit();
                    });
                }
            });
        </script>
        <?php
    }
}
if( is_admin() ){
    EMP_Forms_Fix::init();
}