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Disable Controls During AJAX

This help article describes how to disable a single control during an AJAX update or how to set a global flag to disable a control, and shows examples of each.

You may want to disable control during an AJAX update, so the users won't be able to use it before response end. You can easily disable a control during an AJAX update using the RequestStart andResponseEnd client-side events and changing the disabled value.

Example 1 shows this approach.

Example 1: Prevent the interaction with a control during an AJAX request.

<script type="text/javascript">
    function RequestStart(sender, args) {
        args.EventTargetElement.disabled = true;
    function ResponseEnd(sender, args) {
        args.EventTargetElement.disabled = false;

<telerik:RadScriptManager ID="RadScriptManager1" runat="server">

<telerik:RadAjaxPanel ID="RadAjaxPanel1" runat="server" ClientEvents-OnRequestStart="RequestStart" ClientEvents-OnResponseEnd="ResponseEnd">
    <asp:Button ID="btnUpdate" runat="server" Text="Update" />
    <asp:Label ID="Label1" runat="server"></asp:Label>

Implementing the code in Example 1 will disable any control that has already started a request until its response ends.

If you want to disable AJAX until the current response finishes, no matter which control has started the first request and which is going to make a second one, you can set a global flag as shown in Example 2.

Example 2: Notify the user that an action is in progress.

var AjaxIsActive = false;
function RequestStart() {
    if (!AjaxIsActive) {
        AjaxIsActive = true;
    else {
        alert('Wait for ajax to finish'); return false;
function ResponseEnd() {
    jaxIsActive = false;

See Also

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