Javascript check/uncheck all button for treeview

I want to have a linkbutton that when pressed checks/unchecks all the checkboxes on a treeview. How can I achieve this with Javascript?

I researched and found this code but I can't seem to make it work.

function selectAllNone(value) {
        var tvNodes = document.getElementById("trvMenu");
        var chBoxes = tvNodes.getElementsByTagName("input");
        for (var i = 0; i < chBoxes.length; i++) {
            var chk = chBoxes[i];
            if (chk.type == "checkbox") {
                chk.checked = value;
            }
        }
        return false;
    }