How to empty grid in custom form (with html form elements)

Question

I have a custom made data form, with therein a datagrid with multiple fields. I have made the possibility to add entries, in the background adding rows by adding input elements with the correct names:

<input name='field_id_16[rows][new_row_0][col_id_1]' type='text'>
<input name='field_id_16[rows][new_row_0][col_id_2]' type='text'>

.. etc.

this checkout the correct field and column names, and everything is going as planned. now I also built in the possibility of deleting, and as long I take care of the 'new_row_x' numbering, this all goes well.

now my problem is when the user deletes all entries. I don't have the form elements anymore (because there should be none - when the user removes all datarows) giving a value, and i don't know how to custom update a datagrid which used to elements, back to being empty...?

anybody knows what to do?

greets Rick

Answer 1

After a bit more trying different things, I found out that by just using the field id name and keeping the value empty, submitting the form empties the grid.

see in my case (the grid having database id 16):

<input type='hidden' name='field_id_16' value=''>

empties the grid when submitted.