Example of How To Push Marketo Form Values to DataLayer

form_values_to_datalayer.html

<script>
MktoForms2.whenReady(function (form) {
    form.onSubmit(function(){
        var vals = form.vals();
        dataLayer.push({
            'event': 'marketoFormSubmit',
            'marketoCompany': vals['Company'],
            'marketoLeadSource': vals['LeadSource'],
            'marketoOriginalSource': vals['Original_Source_Detail__c'],
            'marketoCurrentSource': vals['Source_Detail__c']
        });
    });
});
</script>