title: Dynamically/Automatically update price from qty on your magento product page
body: <p>Amend code to Dynamically update price from quantity on product page; works perfectly. Just add the identified code to public_html/js/varien/product.js</p>
  
  <p>Copy and paste the first four lines of the code below into your product.js, before 'if (price > 0 || this.displayZeroPrice)', add the last five lines of code to the very end of the document; your done.  Save the file and watch your price update dynamically. </p>
  
  <pre><code>var qty;
  if($('qty').getValue().length==0 || isNaN($('qty').getValue()) || $('qty').getValue() &lt;= 0) qty = 1;
  else qty = $('qty').getValue();
  price*=qty; 
  if (price &gt; 0 || this.displayZeroPrice) {
  formattedPrice = this.formatPrice(price);
  } else {
  formattedPrice = '';
  }
  
  if ($(pair.value).select('.price')[0]) {
  $(pair.value).select('.price')[0].innerHTML = formattedPrice;
  if ($(pair.value+this.duplicateIdSuffix) &amp;&amp; $(pair.value+this.duplicateIdSuffix).select('.price')[0]) {
  $(pair.value+this.duplicateIdSuffix).select('.price')[0].innerHTML = formattedPrice;
  }
  } else {
  $(pair.value).innerHTML = formattedPrice;
  if ($(pair.value+this.duplicateIdSuffix)) {
  $(pair.value+this.duplicateIdSuffix).innerHTML = formattedPrice;
  }
  }
  };
  }.bind(this));
  },
  formatPrice: function(price) {
  return formatCurrency(price, this.priceFormat);
  }
  }
  Event.observe(window, 'load', function() {
  if ($('qty')) $('qty') .observe('blur', function(e){
  optionsPrice.reload();
  });
  }); 
  </code></pre>
  
  <p>Hope this helps.</p>