title: Textbox is not keeping values or losing values after post back on telerik textbox which are inserted or appended via Javascript
body: <p>I am having a problem with my radTextBox values, the values inserted via JavaScript is being removed after the post back happens but the values inserted through c# are there. I am taking values from radgrid and inserting them into textbox.</p>
  
  <p>The scenario:</p>
  
  <p>1: insert or append values via JavaScript
  2: insert or append values via c# method which triggers postback</p>
  
  <h1>Html Code for Textbox:</h1>
  
  <pre><code>&lt;telerik:RadTextBox ID="rtxtToEmail" runat="server" Width="300px" Skin="Office2007"
                              TextMode="MultiLine" ViewStateMode="Enabled"&gt;
                          &lt;/telerik:RadTextBox&gt;
  </code></pre>
  
  <h1>Html Code for Button that calls JavaScript function:</h1>
  
  <pre><code>&lt;telerik:RadButton ID="rdbtnTo" runat="server" Skin="Office2007" Width="68px" Text="Selected" OnClientClicked="ToSelected" AutoPostBack="false"&gt;
                      &lt;/telerik:RadButton&gt;   
  </code></pre>
  
  <h1>Javascript Code:</h1>
  
  <pre><code>function ToSelected(sender, args) {
                           var grid = $find("&lt;%=rgWOAssignedType.ClientID %&gt;");
                          var DataItem = grid.get_masterTableView().get_dataItems()[grid._selectedIndexes];
                          var keyValues = DataItem.getDataKeyValue("Email");
                          //alert(keyValues); return false;
  
                          if (keyValues != "") {
                              document.getElementById("&lt;%= rtxtToEmail.ClientID %&gt;").value +=
                               keyValues + ";"
                          }
                          return false;
                      }
  </code></pre>
  
  <h1>C# Code on button click event which triggers the post back:</h1>
  
  <pre><code>protected void rbtnToClient_Click(object sender, EventArgs e)
          {
              try
              {
                  #region Fill To CLient Email
  
                  if (ViewState["ClientEmail"] != null)
                  {
                      if (!string.IsNullOrWhiteSpace(ViewState["ClientEmail"].ToString()))
                      {
                          rtxtToEmail.Text += ViewState["ClientEmail"].ToString() + ";";
                      }
                  }
  
                  #endregion
              }
              catch (Exception ex)
              {
                  try { throw new WTLIB.WTException(ex); }
                  catch (WTLIB.WTException eX) { eX.WriteToEventLog(); eX.MessageError(Page); }
              }
          }
  </code></pre>