I was able to do this by using mootools and this is the code.
function ToggleSelection(ctrl, sender)
{
var cblCtrl = $(ctrl);
var Allcbs = cblCtrl.getElements('input');
for(var i=0; i<Allcbs.length; i++)
Allcbs[i].checked = sender.checked;
}
function ToggleSelectAll(ctrl, sender)
{
var AllTrueCount = 0;
var cblCtrl = $(ctrl);
var Allcbs = sender.getElements('input');
for(var i=0; i<Allcbs.length; i++)
if(Allcbs[i].checked)
AllTrueCount++;
if(AllTrueCount == Allcbs.length)
cblCtrl.checked = true;
else
cblCtrl.checked = false;
}
C# code which calls the javascript functions
//Binding event to the checkbox list
cblUSEquities.Attributes.Add("onclick", string.Format("javascript:ToggleSelectAll('{0}', this);", chkAllUSEquities.ClientID));
//binding event to the select all checkbox
chkAllUSEquities.Attributes.Add("onclick", string.Format("javascript:ToggleSelection('{0}', this);", cblUSEquities.ClientID));
As it turns out I did not need to know the id's of all the checkboxes generated by the checkbox list. I was able to add the onclick javascript to those checkboxes by this line
cblUSEquities.Attributes.Add("onclick", string.Format("javascript:ToggleSelectAll('{0}', this);", chkAllUSEquities.ClientID));
Which will add the onclick event to the table that the checkbox list generates.