In .aspx write this java script
<script type="text/javascript">
function myTestFunction() {
if (confirm('Do you want to add another global Space ?')) {
return true;
}
else {
window.location.href="/KB/answers/Dashboard.aspx";
return true;
}
}
</script>
and in code behind.........
call this after save \\
ScriptManager.RegisterStartupScript(this, typeof(string), "confirm",
"myTestFunction();", true);