Checkbox - pass values

Question

Hi,

I have a page with a checkbox that is populated from a sql. The table on the sql is setup as follows.

sopid, Type, DisplayOrder, Deleted.
1      test1  1            False
2      test2  2            False

What i want to do is if check test1 and test2 for example it outputs the sopID to a textbox in the following manor - 1,2 etc... Also if i untick one it removes it from the textbox as well.

Thanks