Jquery & Datepicker - How to protect the value of a textfield from user changes? (and automatically rerendered the value of the calendar)?

Sorry for this simple question but I am really a noob and didn't find what I want in the jquery documentation.

Here is the story:

I have a text field in a form populated by a calendar in jquery (datepicker). I would like to "protect" this textbox. in other word if the user wants to change the value in the 开发者_Python百科textbox (deleting or adding something), the value generated by the calendar is automatically re-rendered.

Thanks for your help!

HTML has the readonly attribute for textareas and input fields.

<input type="text" readonly="readonly" value="Users cannot change me" />

You could do something like this

$('#textfield-id').keydown(function(){
   if($(this).val() == '') {
      //get value from calendar again
      var calText = $('#calendar').val();
      $(this).val(calText);
   }
});