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National Library of Medicine Web Design Policies


1. Federal Guidelines

The Checklist of Requirements for Federal Websites and Digital Services page on the web site provides an excellent list of the must do's and should do's of federal Web site design.

Sites or applications developed in cooperation with NLM, are not held to these federal requirements, but the guidelines below, and the Checklist of Requirements, provide an excellent basis for usable design.

2. Content of Web Pages

2.1. Location of Files and Elimination of Duplication

There should be only one copy of each document that may be pointed to from other pages, documents, document collections, or home pages. For example, there should be only one version of an NLM Fact Sheet, or one version of an NLM report. For consistency and timeliness, individual programs should not create copies of documents but should point to the version where it is maintained by the creator.

3. Navigation/Organization

3.1 Links

All major and minor links should be created using a combination of HTML and style sheets. The use of images to indicate links should be avoided, since the fonts in these buttons cannot be increased using browser controls and appears distorted when viewed in a magnifier software.

3.2 Link to NLM Home Page

A home page for a set of Web pages or application must provide a link to the NLM home page.

3.3 Links to External Sites and Pages

All external links should be valid and clearly identified by including the page title (or appropriate description).

When pointing to sites outside NLM, documents must contain a link to NLM Copyright Information, which covers copyright, a disclaimer about external links, and access restrictions, based on NIH Guidelines.

3.4 Navigation Aids

Navigation aids such as menu bars, a mapped bar or buttons allow the user to move logically through a document, document collection, or home page. Documents should be designed so that users will not have to rely on the browser's navigation aids (e.g., back, forward buttons, history lists).

3.5 Navigation Aids for Multi-page Documents

For a document which is arranged like a book, the end of the page should provide links to:

  • a table of contents
  • the next chapter, section, or page
  • previous chapter (or page)

3.6 Skip Navigation

All HHS pages must provide a method for skipping repetitive navigation.

Go to the HHS web site // for more information.

4. Style/Markup

4.1 Testing of Web Pages

Web pages should be tested with Internet Explorer 11, Safari 5, and Mozilla Firefox (most recent 3 versions). If you are creating a new, unique set of pages, you must test with multiple browsers.

4.2 Titles

Every page shall have a title. The title will be as short as possible but fully informative and specific.

4.3 Meta Tags

META tags may be used between the HEAD tags to judiciously describe the contents of a document. Meta tags are used to enhance ranking or retrieval of Web pages on both local and major search engines. Meta tags for keywords (e.g., <META name="keywords" content="MEDLINE">) or descriptive phrases (e.g., <META name="description" content="The National Library of Medicine (NLM), on the campus of NIH in Bethesda, Maryland, is the world's largest medical library"> may be included.

If possible, remove all META tags generated by HTML editors.

4.4 Fonts and Colors

  • Font family and other layout elements are defined by NLM's official Style Sheets. Use linked style sheets to customize font appearance if necessary.
  • All HTML defined colors must be defined as six-digit hexadecimal numbers. Use linked style sheets to customize color attributes if necessary.

4.5 File Formats

Material intended to be viewed, read or browsed online should be prepared in HTML format for text and gif or jpeg for graphics. Links to files in proprietary or unusual formats should be explicitly noted. For example, if a document or service requires the use of special third-party software (e.g., Adobe Acrobat Reader) place "(PDF)" after the file link.

4.6 Names of URLs and Files

  • Use simple, understandable words, as short as possible.
  • Use lower case, unless upper case is required.
  • Do not use spaces or special characters, except for hyphens or underscores. For example:
    • medicine-image.gif NOT medicine image.gif
    • health_content.html NOT HEALTH CONTENT.html

4.7 Relative URLs

Within a server, relative (and not absolute) links must be used in order to make documents and collections portable. Begin your link at the root of the server. For example:

Express as: <a href="/pubs/fs/nlm.html"></a>
Not as: <a href="//"></a>.

5. Policy

  • Pages shall be "live" and not presented as "under construction."
  • There should be no endorsement of commercial products.

6. Administration

Any NLM organizational unit may contribute pages, documents, document collections, or home pages to the main NLM World Wide Web server. Content and policy approval by the organization's Associate Director or designee must be obtained prior to placement.

7. Questions

If additional information or clarification is needed on any of the above, contact the National Library of Medicine at

Last Reviewed: March 15, 2023