Unable to clear a textbox in Firefox

txtName is the first control in the page. When the page loads initially, it is empty. If there is text in the textbox and the user clicks on Refresh, it is not clearing the text.
At debug, i can see the textbox being cleared, but on page it isnt!!!!.
This happens in Firefox. Works fine in IE.

I have tried , Keeping the textbox outside the updatepanel, enveloping another updatepanel for this textbox alone, Enabling the viewstate, and also removing the clientidmode property.

ASPX:

<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
 <Triggers>
  <asp:AsyncPostBack ControlID="txtName" EventName="TextChanged"/>
 </Triggers>
 <ContentTemplate>
   
   <asp:TextBox ID="txtName" runat="server" OnTextChanged="txtName_TextChanged"
   EnableviewState="false" ClientIDMode="Static">
   </asp:TextBox>

   //Some other controls

 </ContentTemplate>
</asp:UpdatePanel>

C#

protected void page_load()
{
  if(!IsPostBack)
   {
     txtName.Text="";
     UpdatePanel1.Update();
   }
}