Select or Unselect all Checkbox

You can use this free javascript code to Select / Unselect all the checkboxes by selecting a single check box.



checked=false;
function checkedAll (frm1) {
var aa= document.getElementById('frm1');
if (checked == false)
{
checked = true
}
else
{
checked = false
}
for (var i =0; i < aa.elements.length; i++)
{
aa.elements[i].checked = checked;
}
}

OR consider this

tag_name=checkbox array name
checkallName=select all checkbox name

function checkedAll (tag_name,checkallName) {

var checked=false;
checked = document.getElementById(checkallName).checked;

for (var i = 0; i < document.getElementsByName(tag_name).length; i++) {
document.getElementsByName(tag_name)[i].checked = checked;
}

}