Checkboxes is probably one of the most frequently used form controls which come handy in dealing with one to many relationships.
The multiple selective nature of HTML form checkboxes require a convenient way for PHP to process multiple checkbox values, ideally in a single array.
By default, each and every HTML input control including checkboxes posts its value to server-side PHP script by a unique identity that is specified by attribute name=”variable-A”. This approach is generally fine with simple pairs of name and value. However, with multiple checkboxes in the form and probably a lot of them, you will need to assign every single one of them a different name which is quite bitsy and not neat at all.
The solution is for PHP to identify the entire series of checkboxes as a single array accessible via a common index in $_POST. This is achievable by simply inserting the array index operator ‘‘ to the name attribute of the checkbox control:
<input type="checkbox" name="tags" value="1" /> <input type="checkbox" name="tags" value="2" /> <input type="checkbox" name="tags" value="3" /> <input type="checkbox" name="tags" value="4" />
This way, the PHP script processing POST will figure it out automatically and treat $_POST[‘tags’] as an array containing the values 1, 2, 3 and 4:
print_r($_POST['tags']); // output Array (  => 1  => 2  => 3  => 4 )
Now much more handy, huh!