I know there're many answers to this, but none of them works for me. My program is like:
<cml:checkboxes label="Categories" name="categories">
<cml:checkbox label="a" value="a" />
<cml:checkbox label="b" value="b" />
<cml:checkbox label="c" value="c" />
</cml:checkboxes>
Actually it's from CrowdFlower. Now what I want to do is to limit the maximal checked number to 2. I notice that many answers use input labels but that really doesn't work this way, because here the checkbox is embedded in a checkboxes. So anyone can help me with that? Thank you so much!