Hi, I have number of checkboxes and another checkbox for "Select All"

I want to check if the user has selected at least one checkbox. Need modification in javascript

Code:
<head>

<!--script to check, unckeck all boxes-->
<script type="text/javascript">
checked=false;
function All (holiDay) {
	var all= document.getElementById('holiDay');
	 if (checked == false)
          {
           checked = true
          }
        else
          {
          checked = false
          }
	for (var i =0; i < all.elements.length; i++) 
	{
	 all.elements[i].checked = checked;
	}
      }
</script>

<!--script to check at least one checkbox selected-->
<script>
function Validate(){
var all=document.getElementById('holiDay');
for(var i=0;i<all.elements.length;i++){ 
if(all.elements[i].checked)return true; 
}
alert("Please identify what warehouses comply:");  
return false; 
}
</script> 
</head>

<body>
<form name="holiDay"....
....
[]select All

1. <input type="checkbox"....
2. ....
3. ....

</body>
...