POST unchecked HTML checkboxes?

Question

I've got a load of checkboxes that are checked by default. My users will probably uncheck a few (if any) of the checkboxes and leave the rest checked. Is there any way to make the form POST the checkboxes that are **not** checked, rather than the ones that **are** checked?

Answer 1

It is not possible to make the form post what is not checked. However, there are number of ways to accomplish your end goal which, it appears, is to find out what the user did not check.

1) Incorporate JavaScript in your form, then JavaScript can see what is selected and not selected.

2) Modify your server side code so that it can detect what was not submitted. In this case, if the code is expecting 10 checkboxes, but only 8 came through, your code could detect what was missing. For instance, you could number the values in your form, and then when you process the form, you could easily see which values are missing.

3) Build a report that shows what is present and what is missing.

I hope that helps.