title: TypeError: $.ajax is not a function how to solve WITH MY CODE)?
body: <p>When i click on the button, this error is blow up! help pls
  When i click on the button, this error is blow up! help pls</p>
  
  <blockquote>
    <p>TypeError: $.ajax is not a function</p>
  </blockquote>
  
  <pre><code>$(document).on('click', '.item_add', function(e){
          e.preventDefault();
          product_id          = $(".product_id").html();
          product_name        = $(".product_name").html();
          product_price       = parseFloat($(".item_price").html())   
          product_size        = $(".bann-size").val();
          url                 = '/basket_adding/'
          var data            = {};
          data.product_id     = product_id
          data.product_name   = product_name
          data.product_price  = product_price
          data.product_size   = product_size
  
          $.ajax({
              url: url,
              type: 'POST',
              data: data,
              cache: true,
              success: function(data){
                  console.log("OK");
  
  
              },
              error: function(data){
                  console.log(data + "ERROR")
                  alert("Something wrong, try again!")
                  location.reload();
              }
          });
      });
  </code></pre>