How to add a CheckBox to the first column on the DataGrid

DataGrid Select/Reverse:
<input type= "checkbox" Name= "Selall" > all Select/Reverse Selection
Note SelectAll parameters:
DATAGRID1: The ID of the DataGrid
0: The column position of the checkbox in the DataGrid: Starting from 0, the columns not displayed

function SelectAll (Cur,obj,item)
{
var Boolsel = false;
if (cur.checked) boolsel=true;
var objtbchildren = document.all (obj). Children;
for (var i=1; i<objtbchildren.length; i++)
{
if (objtbchildren[i].tagname== "Tbody")
{
var objtrs = Objtbchildren[i].children;
for (var i=0; i<objtrs.length; i++)
{
try{
var objtds = Objtrs[i].children;
var chkctrls = Objtds[item].children;
chkctrls[0].checked = Boolsel;
}catch (e) {}
}
}
}
}



private void Dgmission_itemdatabound (object sender, System.Web.UI.WebControls.DataGridItemEventArgs e)
{
if (E.item.itemindex >-1)
{
(CheckBox) e.item.cells[0]. FindControl ("Chkname")). Attributes.Add ("onclick", "ChangeColor (This)");
}
}


<script language= "JavaScript" >
function ChangeColor (sender)
{
var temp=sender.parentelement;
while (temp.tagname!= ' TR ')
{
Temp=temp.parentelement;
}
if (temp!=null)
{
Temp.style.backgroundcolor= ' Green ';
}
}
</script>