I used implode() to add checkbox values to $message

I have an html file with checkboxes in a table. The values of checked ones are sent through URL to a PHP file where checkboxes are dynamically created on a form.

Once the form is correctly filled, all the data is sent to another PHP file for sending to an email.

I get all the data in the email, except the values of checkboxes when I use implode(',',$var) but I see only one of the values when I use the variable alone ($var).