How to validate multiple checkbox?

var adfa=0;
var chk=document.getElementById("tbl");//table id
for(var i=0;i < chk.rows.length;i++)
{
var inputs = chk.rows[i].getElementsByTagName('input');
if(inputs[0].checked==true)
{
adfa=1;
}
}
if(adfa==1)
{
//alert("true");
if(val=='delete'){
var ans=confirm('Are you sure want to delete?');
if(ans)
document.forms[id].submit();
}
}else
{
alert("No entry was selected to be deleted");
}