dotjs script, amazon.co.uk: add Euro prices to all price tags

amazon.co.uk.js

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/*globals define: false, window: false, jQuery: false */


var scripts = [],
  scriptTag;

// Are there relevant price elements?
if ( jQuery(".price, .ourprice, .priceLarge, .s9Price").length ) {

  // If the current exchange rate is known, enhance the price listing.
  if ( getRate() ) {
    updateProductPage();
  }
  // If not, make the relevant functions available to the "outside" page and
  // trigger the fetch+update process.
  else {
    scripts.push( getRate.toString() );
    scripts.push( fetchRate.toString() );
    scripts.push( setRate.toString() );
    scripts.push( updateProductPage.toString() );

    scriptTag = document.createElement("script");
    scriptTag.innerHTML = scripts.join(";");
    document.head.appendChild(scriptTag);

    fetchRate();
  }
}


// Returns the current numeric GBP-to-EUR exchange rate -- or `0` if there's
// no current rate stored.
function getRate() {
  var details = JSON.parse( window.localStorage.getItem("gbp-to-eur-rate") );

  if ( details && details.date === ( new Date() ).toDateString() ) {
    return details.rate;
  }

  return 0;
}


// Requests the current exchange rate from YQL -- the returned script will
// automatically trigger `setRate()`.
function fetchRate() {
  jQuery.getScript("http://query.yahooapis.com/v1/public/yql?q=SELECT%20col0%20FROM%20csv%20WHERE%20url%3D%22http%3A%2F%2Fdownload.finance.yahoo.com%2Fd%2Fquotes.csv%3Fs%3DGBPEUR%3DX%26f%3Dl1%26e%3D.csv%22&format=json&callback=setRate");
}


// Stores the current exchange rate in localStorage.  Called by the YQL call
// (JSONP).
function setRate(data) {
  window.localStorage.setItem(
    "gbp-to-eur-rate",
    JSON.stringify({
      date: ( new Date() ).toDateString(),
      rate: +data.query.results.row.col0
    })
  );

  updateProductPage();
}


// Iterate over all price elements and add the German EUR price (incl./excl.
// VAT).
function updateProductPage() {
  jQuery.each( jQuery(".price, .ourprice, .priceLarge, .s9Price"), function( i, elem ) {
    var $elem = jQuery(elem),
      gbpPrice = +( $elem.text().substr(1) ),
      dePrice = ( gbpPrice * getRate() ).toFixed(2);

    if (gbpPrice) {
      $elem.html( "£" + gbpPrice + "&nbsp;<span style='font-weight: normal; font-size: 85%'>(€" + dePrice + ")</span>" );
    }
  });
}