Java Script To check MultipleCheckBox Inside the GridView

function SelectheaderCheckboxes(headerchk, GVID) {
    var gvcheck = document.getElementById(GVID);
    var i;
    var inputbox;
    //Condition to check header checkbox selected or not if that is true checked all checkboxes
    if (headerchk.checked) {
        for (i = 0; i < gvcheck.rows.length; i++) {
            inputbox = gvcheck.rows[i].getElementsByTagName('input');
            inputbox[0].checked = true;
        }
    }
    //if condition fails uncheck all checkboxes in gridview
    else {
        for (i = 0; i < gvcheck.rows.length; i++) {
            inputbox = gvcheck.rows[i].getElementsByTagName('input');
            inputbox[0].checked = false;
        }
    }
}