title: Why am I getting an NaN value?
body: <p>My jQuery is:</p>
  
  <pre><code>$("#listDB").on("change", ".qfStyle", function(event) {
      var id = $(this).parents("tr").find('.itemCbox').val();
      $qnty = $("#qnty"+id);
      $unit = $("#unit"+id);
      $price = $("#price"+id);
  
      if($(this).parents("tr").find('.pbo').text()=="Kilos")
      {
          if(this.value&lt;1)
          {
              $qnty.text(this.value*1000);
              $unit.text("gm");
  
              var data = "action=getPrice&amp;id="+id;
              $.post("addBill.php", data, function(json) {
                  alert(json.price);
                  $price.text(json.price*this.value);
              }, 'json');
          }
      }
  });
  </code></pre>
  
  <p>The JSON data returned by the server is:</p>
  
  <blockquote>
    <p>{"price":"52.00"}</p>
  </blockquote>
  
  <p>Here, <code>this</code> refers to a textbox. I'm getting the value <code>NaN</code> for the expression:</p>
  
  <pre><code>$price.text(json.price*this.value);
  </code></pre>
  
  <p>But I've ensured that both <code>this.value</code> and <code>json.price</code> are both numbers. So, why do I get NaN when I multiply them?</p>