Prevent Input on TextBox ASP.NET using JavaScript

This Example useful when we don't want to allow user input on Textbox.

Like Example: Use Calender Extender on Textbox and want only selected date from Calender. If user type wrong date format then error will be occurred. So this example will helpful to not allow input from user.

Using Code:

Write this script in Page Design Source under <Body> tag.

<asp:ScriptManager runat="server" ID="scrp1"></asp:ScriptManager>

<script type="text/javascript">
   function preventInput(evnt) {

      if (evnt.which != 9) evnt.preventDefault();

   }

</script>

Now Call this script on textbox.

<asp:TextBox ID="txtDuedate" runat="server" TabIndex="18"

onkeydown="javascript:preventInput(event);" Enabled="False"></asp:TextBox>

Everything is done and set.