This experimental research project has concluded. The research prototype application is no longer supported or maintained by OCLC services.

The information on this page is provided for historical purposes only. Please note this content may include details that are out-of-date and broken links.

Thank you for your interest, and please explore the OCLC Research website to learn more about our current research.


Got a book title from an online bookseller?  Check whether your local library has it. Jon Udell’s LibraryLookup bookmarklet made it possible to check your local library’s online catalog directly from (or, or other book sites) with a single click in the browser. Unfortunately, many books come in multiple editions and the bookmarklet would often fail to find a match because the library held a different edition. This xISBN-enhanced version improves those changes by finding other manifestations of the same work and including them in the search.

Note: This prototype has been moved to production status and subsequently enhanced in various ways by the xISBN Support team.


Readers everywhere use (or, or other book sites) to find books of interest and then wonder if the book is available at the local library. We love John Udell's LibraryLookup bookmarklet which makes this easy: when you have a book information page from an online bookseller displayed in your browser, you simply click on Jon's LibraryLookup bookmarklet to automatically check your library's OPAC for books with the same ISBN.

Jon's bookmarklet does exact matches on single ISBNs. We enhanced this concept by embedding, behind the scenes and invisible to the user, OCLC Research's xISBN lookup service. After retrieving the ISBN of the desired book from the page, our bookmarklet searches an OCLC Research database of related ISBNs, and then returns the ISBNs of other books in WorldCat related to the sought-after book. (The ISBNs together approximately make up a "FRBR work".) The bookmarklet then checks your library's catalog for those ISBNs.

When you are searching for a book in a library, you probably don't care which specific edition you get. We use the power of WorldCat, and OCLC Research's FRBR algorithm, to locate other possible ISBNs for the book you're looking for.


Jon Udell’s bookmarklet demonstrated that Web user interfaces are essentially just Web services. URL patterns are URL patterns and markup patterns are markup patterns. Despite the similarity of purpose found in book vendor and OPAC systems, some of those patterns are easier to deal with than others, but with rare exceptions the bookmarklet was able to compensate. Incorporating the xISBN service into the mix demonstrated the leverage possible by mashing up simple loosely-coupled applications.

The bookmarklet idea is clever, but unfortunately it doesn’t scale well because it must be installed into each individual browser to work. These basic ideas, though, are now being used by WorldCat Local and Dynamic OPAC Linking to WorldCat to connect users directly to their local library systems.


In Jon's bookmarklet, the JavaScript code was completely contained within the bookmarklet itself. Because of the size limitation of bookmarklets and the additional functionality needed, this wasn’t possible for the xISBN bookmarklet. The solution was to change the bookmarklet to download a JavaScript file from the server and execute that to bypass the size restriction.

The keys to making the bookmarklet work were to configure it with the combination of OPAC type and base URL. From these clues, the bookmarklet could deduce the URL pattern and redirect the browser to the OPAC. During the prototype phase, the list of supported libraries was in the dozens and was maintained manually. Since then, this information has been collected in the WorldCat Registry where supported OPACs now number in the thousands and can be maintained collectively. This decoupling of the OPAC information from the bookmarklet code itself also allows this information to be used by other systems such as WorldCat Local and Dynamic OPAC Linking to WorldCat.


In Jon Udell’s original librarylookup bookmarklet, the OPAC type and baseURL were hardcoded in the bookmarklet. If either of these changed, the bookmarklet had to be reinstalled.

In our original xISBN Bookmark variation, the information for each OPAC was stored in an OAI repository and the bookmarklet was configured with the OAI identifier. When the bookmarklet was invoked, it did an OAI “GetRecord” request on the repository and constructed the target URL from the clues in the response. If the OPAC type or baseURL changed, the OAI repository could be updated and the bookmarklets would continue to work as before.

Since it was ported to a production environment, the OAI repository solution has been replaced by the WorldCat Registry which allows the OPAC configuration information can be maintained collaboratively.

More Information

Most recent updates: Page content: 2009-08-11 Prototype: 2003-11-26


This activity is part of ResearchWorks. Use of our prototypes is subject to OCLC's terms and conditions. By continuing past this point, you agree to abide by these terms.

Try the online demo

Note: This is the latest production version and has been significantly enhanced since its research prototype phase.

  1. Search for your local library.
  2. Install the Bookmarklet on your computer.
    Drag a library's link to your IE browser's links toolbar. You might try, for example, Seattle Public Library.
  3. Next, find a book description at or (e.g. Libraries in the Ancient World; Double Fold; Lonesome Dove).
  4. Click on your new bookmark to look it up in the library's catalog.


Jeff Young