use below javascript to check all the child node when you check parent node
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript">
$(function () {
$("[id*=TreeViewForMasters] input[type=checkbox]").bind("click", function () {
var table = $(this).closest("table");
if (table.next().length > 0 && table.next()[0].tagName == "DIV") {
//Is Parent CheckBox
var childDiv = table.next();
var isChecked = $(this).is(":checked");
$("input[type=checkbox]", childDiv).each(function () {
if (isChecked) {
$(this).attr("checked", "checked");
} else {
$(this).removeAttr("checked");
}
});
} else {
//Is Child CheckBox
var parentDIV = $(this).closest("DIV");
if ($("input[type=checkbox]", parentDIV).length == $("input[type=checkbox]:checked", parentDIV).length) {
$("input[type=checkbox]", parentDIV.prev()).attr("checked", "checked");
}
//else {
// $("input[type=checkbox]", parentDIV.prev()).removeAttr("checked");
//}
}
});
})
</script>