title: Simple JavaScript addition issues
body: <p>I'm not so good with JS and for some reason when I try to add two fields together it joins them rather than adding the sum together.. this is the code I'm trying to use..</p>
  
  <pre><code>    function calculateTotal() {
  
          var postageVal = document.getElementById('postage').value; //$68.50
          var subtotalVal = document.getElementById('subtotal').value; //$378.00
  
          var postage = postageVal.substr(1); //68.50
          var subtotal = subtotalVal.substr(1); //378.00
          var totalVal = postage+subtotal;
  
          alert(postage);
          alert(subtotal);
          alert(totalVal);
  
      };
  </code></pre>
  
  <p>The totalVal is echoing/alerting out 68.50378.00 rather than adding them together.. could someone please tell me where I've gone wrong? :( The idea is to update the "total" textfield with totalVal, but I haven't gotten that far yet!</p>