National Library of Medicine Web Application/Site Development Guidelines
This Style Guide for the National Library of Medicine (NLM) explains the markup and design requirements for all NLM Web projects, along with various standards and best practices. NLM Web pages must be authored in valid XHTML 1.0 Transitional and styled with valid Cascading Style Sheets and be coded in order to ensure accessibility.
NLM is committed to serving the entire public, and that means striving to ensure that all pages of our site are accessible to the greatest possible number of people and Assistive Technology devices.
Browsers and Scripts
The use of HTML markup aimed at a specific browser (e.g., Microsoft Internet Explorer) should be avoided.
- As of March 2018, NLM supports the following browsers:
- Android 4.3+
- Blackberry 10
- Chrome 62+
- Firefox 56+
- Internet Explorer (IE) Mobile 10+
- Internet Explorer 11 (IE11), Edge Browser 14+
- Opera 49+
- Opera Mini
- Opera Mobile 12.1+
- Safari 10+
NLM recommends the use of the UTF-8 character set for Web pages so that non-English languages and diacritics are more effectively displayed. The coding to be placed in the HEAD tag of all Web pages is:
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
NLM's Web design policies.
Guidelines for appropriately branding a Web site or application in development for NLM, and when to use the official NLM header and footer.
Includes NLM's official Cascading Style Sheets. If you wish to create your own style sheets, please discuss your requirements with your NLM project coordinator.
Web page examples showing how markup will display the NLM css.
Referring to an NLM product in print.
Quality assurance checklist for Web applications.
HTML and CSS
NLM Web pages must be authored in HTML5. All HTML must validate.
Web pages must use valid Cascading Style Sheets (CSS) to control typography, color, and other layout elements. Style sheets must be linked in a way that accommodates the capabilities of new and old browsers.
National Library of Medicine (NLM) Web pages must be authored in structural HTML5. Page authors should follow accessibility guidelines in compliance with Section 508 and the WAI so that our site’s content will be made available to the widest possible number of people, browsers, and Internet devices. In addition, all HTML must validate.
- What is HTML5? (www.w3schools.com)
- A introduction to HTML5
- HTML Accessibility (National Library of Medicine Accessibility)
- Making sure your pages can be read by all visitors, browsers, and devices.
- HTML Validation (W3C's Unified Validator)
- Ensure interoperability by avoiding errors and sticking to coding standards.
Web sites and web-based applications must use valid Cascading Style Sheets (CSS) to control typography, color, and other layout elements. Style sheets must be linked in a way that accommodates the capabilities of new and old browsers.
- Cascading Style Sheets (W3C Cascading Style Sheets home page)
- What is CSS?
- NLM Style Sheets
- NLM's official Cascading Style Sheets.
- CSS Validation (W3C CSS Validation Service)
- Ensure style sheets are error-free.
If you wish to create your own style sheets, please discuss your requirements with your NLM project coordinator.