//checks all DataGrid CheckBoxes with the given name with the given value
function CheckAllDataGridCheckBoxes(aspCheckBoxID, checkVal) {

    re = new RegExp(':' + aspCheckBoxID + '$')  //generated control name starts with a colon

    for(i = 0; i < document.forms[0].elements.length; i++) {

        elm = document.forms[0].elements[i]

        if (elm.type == 'checkbox') {

            if (re.test(elm.name)) {

                elm.checked = checkVal

            }
        }
    }
}