c# - How to maintain the focus on same control after asynchronous postback? -

i have 3 textboxes , 1 in updatepanel refresh every 4 seconds. during refresh controls not in update panel loosing focus. want keep focus on controls.

here code:

<asp:updatepanel id="upnlchat" runat="server">     <contenttemplate >         <asp:textbox id="txtchatbox" readonly="true" textmode="multiline"              cssclass="mymultitextboxclass" runat="server"></asp:textbox>      </contenttemplate>       <triggers>       <asp:asyncpostbacktrigger controlid="timerchat" />        </triggers>     </asp:updatepanel>     <asp:timer id="timerchat" interval="4000" runat="server" ontick="timerchat_tick" ></asp:timer>         <table>         <tr><td>user: </td><td colspan="2"><asp:textbox id="txtuser" runat="server" ></asp:textbox><br /></td>         <td>             <asp:requiredfieldvalidator id="requiredusername" runat="server" errormessage="username required" controltovalidate="txtuser" ></asp:requiredfieldvalidator> </td></tr>         <tr><td>message: </td><td><asp:textbox id="txtmsg" cssclass="mymsg" textmode="multiline" onkeydown="if (event.keycode == 13) { btnsend.focus(); this.form.submit();  }"  runat="server"></asp:textbox></td>         <td colspan="2"><asp:button id="btnsend" runat="server" onclick="btnsend_click"                  onclientclick="scroll()" text="send" />         </td></tr>                 </table> 

can please me?

here modified version of @darshan's script uses jquery. solution because 1 script work updatepanels don't have write code each , every updatepanel.

my modifications are:

• uses jquery
• performs null checks
• doesn't pollute global namespace
• edit: tabbing works expected textboxes autopostback.

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/* retain element focus after updatepanel postback ***************************************************/ jquery(function ($) {     var focusedelementid = "";     var prm = sys.webforms.pagerequestmanager.getinstance();      prm.add_beginrequest(function (source, args) {         var fe = document.activeelement;         if (fe != null) {             focusedelementid = fe.id;         } else {             focusedelementid = "";         }     });      prm.add_endrequest(function (source, args) {         if (focusedelementid != "") {             $("#" + focusedelementid).focus();         }     }); }); 

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chosen.jquery

this version work chosen jquery plugin.

/* retain element focus after updatepanel postback ***************************************************/ jquery(function ($) {     var focusedelementselector = "";     var prm = sys.webforms.pagerequestmanager.getinstance();      prm.add_beginrequest(function (source, args) {         var fe = document.activeelement;         focusedelementselector = "";          if (fe != null) {             if (fe.id) {                 focusedelementselector = "#" + fe.id;             } else {                 // handle chosen js plugin                 var $chzn = $(fe).closest('.chosen-container[id]');                 if ($chzn.size() > 0) {                     focusedelementselector = '#' + $chzn.attr('id') + ' input[type=text]';                 }             }         }     });      prm.add_endrequest(function (source, args) {         if (focusedelementselector) {             $(focusedelementselector).focus();         }     }); });