No validation:
<asp:Button UseSubmitBehavior="false" OnClientClick="$('body').css('cursor', 'wait'); $('.Buttons').attr('disabled', 'true');" ID="ButtonBack" runat="server" Text="aa" ValidationGroup="novalidation" OnClick="ButtonBack_Click" />
With validation
<asp:Button UseSubmitBehavior="false" OnClientClick='if (Page_ClientValidate("vg")) { $("body").css("cursor", "wait"); $(".Buttons").attr("disabled", "true");}; '
ID="ButtonReview" runat="server" Text="Next" OnClick="ButtonReview_Click"
ValidationGroup="vg" />
And also add following code into master page or web forms page to reset cursor to normal, if validation failed
<script type="text/javascript">
function pageLoad() {
$('body').css('cursor', 'auto');
}
</script>