Jquery Help

Jquery Help

I am brand new to JQuery and am trying to help my daughter troubleshoot an assignment that is due tomorrow.  She is trying to do a simple To Do List.  She followed a video instruction on line and the video says to use .on(click, ), but everything else I am reading shows to use .click.
 
Here is the HTML that she did based on the video:
 
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
        <title>Test</title>
        <script type="text/javascript" src="jquery.js"></script>
        <script type="text/javascript" src="scripts.js"></script>       
    </head>         





 <body>
                     <h1>To Do - Today</h1>
                        <hr />
                        <ul id="todolist">
                          <li><input type="checkbox" class="done" /> Sample 1 <button class="delete">Delete</button></li>
                          <li><input type="checkbox" class="done" /> Sample 1 <button class="delete">Delete</button></li>
                        </ul>





                        <input type="text" id="newtext"> <button id="add">Add</button>
    </body>
</html>


 
Here is the code that she did based on the video:
 
function addListItem() {
 var text = $("#newtext").val();
 $("#todolist").append('<li> <input type="checkbox" class="done" />'+text+'<button class="delete">Delete</button></li>');
 $("#newtext").val('');
}



function deleteItem() {
 $(this).parent().remove();
}

function finishItem() {
 if ($(this).parent().css('textDecoration') == 'line-through') (
  $(this).parent().css('textDecoration', 'none');
 } else {
  $(this).parent().css('textDecoration', 'line-through')
}}





$(function() {
 $("#add").on('click', addListItem);

 $(document).on('click', '.delete', deleteItem);
 $(document).on('click', '.done', finishItem);
});


None of the commands are working.  I have two questions.
1)  Does it matter whether she uses the .on(click, ) method or the .click method?
2)  Why is this code not working...does anybody see what the problem is?
3)  Does a script.js file have to have the $(document).ready( function() {  at the start of the file to run?  I noticed it is not in the .on(click, ) document?
 
Thank you very much for your help!