How to use automatically created checkboxes in PHP?

I made checkboxes

<?php
    for($i=0;$i<100;$i++){
    echo '<input type="checkbox">';
    }
    //if you want to add a submit btn at last
    echo '<input type="submit" value="Submit">';
    ?>

How to use these checkboxes? If i want to change the values and save to an array. I have a default array to compare with the new array.(changed values) and if those values have changed i want to use this alert message (Changed successfull).