Easy Checkbox Required

One pain point in HTML5 validation is checkbox groups as you cannot simply use the require" attribute as it would require the inclusion of each checkbox that is part of the group. This script fixes that by using a data attribute -- data-checkbox-required -- to indicate the requirement.

Adding the data-checkbox-required attribute to one or more checkboxes in a group would require at least one checkbox be chosen, but you can specify lower and upper bounds by giving a value to the attribute. For example:

<input type="checkbox" name="test[]" value="1"
       data-checkbox-required="3"
       >

Would require at least 3 checkboxes in the group be checked

<input type="checkbox" name="test[]" value="1"
       data-checkbox-required="3-5"
       >

Would require at least 3, but no more than 5 checkboxes in the group be checked.

<input type="checkbox" name="test[]" value="1"
       data-checkbox-required="0-5"
       >

Would require any number (including 0), up to 5 checkboxes in the group be checked.