Select All/None checkboxes

This's just a small tip I want to take note.
- Here is the script:  
 

<script> 

   function checkboxEvent(){ 

      var select_ckb = document.getElementById("select-all");

      var select_list = document.getElementsByClassName("select");

      if(select_ckb.checked) { 

          for(var i=0; i<select_list.length; i++) { 

                select_list[i].checked=true; 

          }; 

       } else { 

          for(var i=0; i<select_list.length; i++) { 

              select_list[i].checked=false; 

           }; 

       };

    }; 

</script>

- HTML file:

....

<input type="checkbox" id="select-all" onchange="checkboxEvent();"> 

<input type="checkbox" class="select"> 

<input type="checkbox" class="select">

.... 


Enjoy this!
Trinh.