Dynamic Form Field Validation

Hello All. I need a sample of a form that validates dymnically created form fields. Specifically checkboxes and text fields all in one form. On the form a user chooses a product by selecting a checkbox. I have the syntax for this and it is working propery. I need to add another function to make sure the users enters a quantity. Here is my script: <script language="javascript"> function checkForm() { var el = document.forms[0].elements; for(var i = 0 ; i < el.length ; ++i) { if(el[i].type == "checkbox") { var checkboxgroup = el[el[i].name]; var itemchecked = false; for(var j = 0 ; j < checkboxgroup.length ; ++j) { if(checkboxgroup[j].checked) { itemchecked = true; break; } } if(!itemchecked) { alert("Please select a product"); if(el[i].focus) el[i].focus(); return false; } } } return true; } } </script>