I've added this script to my EditForm.aspx and it works perfectly, except for one issue. I added an "Order" column of type number to each of the relationshipLists and introduced this column as the relationshipListSortColumn. The resulting sort order of the child options is by "ID" and not by "Order". If I set the SortColumn to "Title" or "ID" it sorts as expected.
<script
src="https://code.jquery.com/jquery-2.2.4.min.js"
integrity="sha256-BbhdlvQf/xTY9gja0Dq3HiwQF8LaCRTXxZKRutelT44="
crossorigin="anonymous"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery.SPServices/2014.02/jquery.SPServices-2014.02.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$().SPServices.SPCascadeDropdowns({
relationshipList: "{7E9AA6F4-6E33-4533-8144-FFB9364E8C18}",
relationshipListParentColumn: "Chapter",
relationshipListChildColumn: "Title",
relationshipListSortColumn: "Order",
parentColumn: "Chapter Required Field",
childColumn: "Section",
debug: true
});
$().SPServices.SPCascadeDropdowns({
relationshipList: "{5BCE574B-0E5E-471A-A72C-792ECD552234}",
relationshipListParentColumn: "Section",
relationshipListChildColumn: "Title",
relationshipListSortColumn: "Order",
parentColumn: "Section",
childColumn: "Subsection",
debug: true
});
}
);
</script>