$ not defined ajax request in javascript

Question

I am trying to send a php file to some values ​​using ajax, but in ajax call I get the following error

Uncaught ReferenceError: $ is not defined 

at the beginning of the line for the ajax request as follows:

$.ajax({
  type: "POST",
  url: 'program3.php',
  data: {
    player1name: player1name.value,
    player2name: player2name.value,
    playtopoints: playtopoints.value,
    delay: delay.value,
    numgames: numgames.value,
    gamesplayed: gamesplayed.value,
    p1turn: p1turn.value,
    p2turn: p2turn.value,
    p1total: p1total.value,
    p2total: p2total.value
  },
  success: function (data) {
    rolling = data;
  }
});            

At first I thought that refrence for ajax might be needed, so I added the following line before javascript in the html page:

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>

but I still get erro, can anyone offer insight?

I also have all the data variables that are defined as follows:

var player1name = document.JForm.p1name.innerHTML;

Is this the correct way to assign them?

Answer 1

src script - , http https.

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>

Answer 2

, , script, .

<!-- access from http resolves to this -->
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>

<!-- local access resolves to this -->
<script src="file://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>

, script . , $ undefined.