Stop function start when a button is pressed

Question

I have a function that rotates a div inside another div. How can I start and stop the rotation of a button at the click of a button. One button to start spinning another to stop it. And is there a way to rotate a div only when I press the slider to the right or left, not like it is now on the mouse move? Please help. Function for rotating the div:

var img = $(".inner");

if (img.length > 0) {
  var offset = img.offset();

  function mouse(evt) {
    var center_x = (offset.left) + (img.width() / 2);
    var center_y = (offset.top) + (img.height() / 2);
    var mouse_x = evt.pageX;
    var mouse_y = evt.pageY;
    var radians = Math.atan2(mouse_x - center_x, mouse_y - center_y);
    var degree = (radians * (180 / Math.PI) * -1) + 90;
    img.css('-moz-transform', 'rotate(' + degree + 'deg)');
    img.css('-webkit-transform', 'rotate(' + degree + 'deg)');
    img.css('-o-transform', 'rotate(' + degree + 'deg)');
    img.css('-ms-transform', 'rotate(' + degree + 'deg)');
  }
  $(".inner").mousemove(mouse);
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="inner" style="width:100px; height:100px; background-color:black; display:block; ">

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Answer 1

You can set classto determine if it was pressed img:

Self Click Version:

var img = $(".inner");
var offset = img.offset();

function mouse(evt) {
  var center_x = (offset.left) + (img.width() / 2);
  var center_y = (offset.top) + (img.height() / 2);
  var mouse_x = evt.pageX;
  var mouse_y = evt.pageY;
  var radians = Math.atan2(mouse_x - center_x, mouse_y - center_y);
  var degree = (radians * (180 / Math.PI) * -1) + 90;
  img.css('-moz-transform', 'rotate(' + degree + 'deg)');
  img.css('-webkit-transform', 'rotate(' + degree + 'deg)');
  img.css('-o-transform', 'rotate(' + degree + 'deg)');
  img.css('-ms-transform', 'rotate(' + degree + 'deg)');
}

img.on('click', function(e) {

  $(this).toggleClass('clicked');

});

img.on('mousemove', function(evt) {
  if (!img.hasClass('clicked')) {
    mouse(evt);
  }
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="inner" style="width:100px; height:100px; background-color:black; display:block; ">

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Click the "Version" button:

var img = $(".inner");
var offset = img.offset();

function mouse(evt) {
  var center_x = (offset.left) + (img.width() / 2);
  var center_y = (offset.top) + (img.height() / 2);
  var mouse_x = evt.pageX;
  var mouse_y = evt.pageY;
  var radians = Math.atan2(mouse_x - center_x, mouse_y - center_y);
  var degree = (radians * (180 / Math.PI) * -1) + 90;
  img.css('-moz-transform', 'rotate(' + degree + 'deg)');
  img.css('-webkit-transform', 'rotate(' + degree + 'deg)');
  img.css('-o-transform', 'rotate(' + degree + 'deg)');
  img.css('-ms-transform', 'rotate(' + degree + 'deg)');
}

$('#Stop').on('click', function(e) {
  img.addClass('clicked');
});

$('#Start').on('click', function(e) {
  img.removeClass('clicked');
});

img.on('mousemove', function(evt) {
  if (!img.hasClass('clicked')) {
    mouse(evt);
  }
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="inner clicked" style="width:100px; height:100px; background-color:black; display:block; ">
</div>
<button id="Start">Start</button>
<button id="Stop">Stop</button>

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Answer 2

With jQuery you can use:

$('selector').on('click', function(){

}

, Jquery: http://api.jquery.com/animate/