Plz verify the steps to create a popup everytime the user hits OK button in SP list

Question

1. Open Share point Designer and Open the site.
2. Go to the Share point list which you want to customize.(Lists => ) Select "EditForm.aspx"
3. Find the end tag of the PlaceHolderMain section

4. Insert the following script above the </asp:Content> line:

   /* i know javascript is not exactly right. Please suggest what changes do i need to make in the javascript */

   <script type=”text/javascript”>
   var x=document.getElementsByTagName(“input”);
   for (var i=0; i<x.length; i++)
   {
   if (x.item(i).type==”button” && x.item(i).value==”Save and Close”)
   {
   x.item(i).style.display=”none”;
   }
   }
   </script>