How do I turn off javascript code from back end?

I have a project where the user wanted to be able to do inserts and updates from the gridview. I used a solution I found here:
http://www.codeproject.com/KB/webforms/addupdate.aspx?msg=3856488#xx3856488xx
I use the following script to modify the Edit and Delete commands to Add:
 <script>
//    this function overwrites Edit with Add
    function FixGrid(idGrid)
    {
      try
      {
         if (/Firefox[\/\s](\d+\.\d+)/.test(navigator.userAgent))
         {
            var Parts = idGrid.lastChild.childNodes[1].childNodes[1].innerHTML.split(">Edit<");
     ...