JavaScript Copying value from one text field to another

I have created a button to run the following actions:

1. Mouse Down > Execute a menu item > File>Print...
2. Mouse Down > Run a JavaScript as follows

                                                  function copyToAnother()

                                                  {

                                                  var text1 = document.getElementById(id_of_first_text_field);

                                                  var text2 =document.getElementById(id_of_second_text_field);

                                                  text2.value = text1.value; // copy value of Ist field into second Field

                                                  }

        This is to try to copy a numerical vale from a text field (Text1) to another text field (Text2)

     3. Mouse Down > Reset a form (all fields except Text2)

     4.  I then want to use a JavaScript to autosave the form

     5.  When this saved file is opened, I  want to use a JavaScript to move the value from the Text2 field to the Text1 field

I would like to do this with using a global object for sequential numbering.  So far, my JavaScript doesn't seem to produce results.  Is there an easier way to accomplish the above tasks?