getting an error in the console (Uncaught ReferenceError: $ is not defined)

getting an error in the console (Uncaught ReferenceError: $ is not defined)

I am getting an error when trying run this script:

Uncaught ReferenceError: $ is not defined


  2. <script>
  3.   $(function() {
  4.     $( "#slider-range" ).slider({
  5.       range: true,
  6.       min: 0,
  7.       max: 500,
  8.       values: [ 75, 300 ],
  9.       slide: function( event, ui ) {
  10.         $( "#amount" ).val( "$" + ui.values[ 0 ] + " - $" + ui.values[ 1 ] );
  11.       }
  12.     });
  13.     $( "#amount" ).val( "$" + $( "#slider-range" ).slider( "values", 0 ) +
  14.       " - $" + $( "#slider-range" ).slider( "values", 1 ) );
  15.   });
  16.   </script>
what's missing here?