Source: php.net
To get form submission result sent as an array to PHP script name the <input>, <select> or <textarea> elements like this:
<input name="MyArray[]" /> <input name="MyArray[]" /> <input name="MyArray[]" /> <input name="MyArray[]" />
Notice the square brackets after the variable name, that’s what makes it an array.
It’s also possible to assign specific keys to your arrays:
<input name="AnotherArray[]" /> <input name="AnotherArray[]" /> <input name="AnotherArray[email]" /> <input name="AnotherArray[phone]" />
The AnotherArray array will now contain the keys 0, 1, email and phone. Specifying array keys is optional in HTML. If you do not specify the keys, the array gets filled in the order the elements appear in the form. Our first example will contain keys 0, 1, 2 and 3.
Shabbir Mirza 