I am trying to return all approvals for a specific Catalog Item, i have the script working but i want to run when you select on a module in the navigation. 

Here is my script: 

var approvalTest = Class.create();
approvalTest.prototype = Object.extendsObject(AbstractAjaxProcessor, {

populateApprovals: function() {
        var approvals = [];
        var grApprovals = new GlideRecord('sysapproval_approver');
        grApprovals.addQuery('state', 'requested');
        grApprovals.query();

        while (grApprovals.next()) {
            var grRitm = new GlideRecord('sc_req_item');
            grRitm.addQuery('active', true);
            grRitm.addQuery('sys_id', grApprovals.sysapproval);
            grRitm.query();
            if (grRitm.next()) {
                approvals.push(grApprovals.getUniqueValue());

            }

        }
        return approvals.join(',');

    },





    type: 'approvalTest'
});

here is the filter but it returns null , is there a way to run javascript via a filter,

here is the module setup: