Beginner trying to get first command to work

Beginner trying to get first command to work

trying to get this simple .html command to change the text in the button from "it's a button" to "my button" like this guy does in this tutorial  https://youtu.be/G-POtu9J-m4?t=24s except it's not working for me. I have jquery-1.11.3 in the same folder that my index.html is in. I don't know what could be wrong.

  3. <!doctype html>
  4. <!--[if lt IE 7]>      <html class="no-js lt-ie9 lt-ie8 lt-ie7" lang=""> <![endif]-->
  5. <!--[if IE 7]>         <html class="no-js lt-ie9 lt-ie8" lang=""> <![endif]-->
  6. <!--[if IE 8]>         <html class="no-js lt-ie9" lang=""> <![endif]-->
  7. <!--[if gt IE 8]><!--> <html class="no-js" lang=""> <!--<![endif]-->
  8.     <head>
  9.         <meta charset="utf-8">
  10.         <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
  11.         <title></title>
  12.         <meta name="description" content="">
  13.         <meta name="viewport" content="width=device-width, initial-scale=1">
  14.         
  15.  <script src="jquery-1.11.3.js"></script>
  16.       
  17.     </head>
  18.     <body>                   
  19.                         <button id="thisButton">it's a button</button>
  20.         <script>
  21.             $(function(){
  22.            $('thisButton').html('my button');          
  23.            });           
  24.         </script>

  26.     </body>
  27. </html>