Handheld Device Markup Language (HDML)
Handheld Device Markup Language (HDML) is an early markup language designed specifically for creating content for handheld devices, such as mobile phones and PDAs. Developed by Unwired Planet (now known as Openwave) in the mid-1990s, HDML was a precursor to the more popular and widely adopted Wireless Markup Language (WML).
HDML was created to address the limitations of handheld devices at that time, including small screen sizes, limited processing power, and low-bandwidth connections. The language provided a simple, text-based format for displaying content on these devices, enabling users to access web pages and other online services from their mobile phones or PDAs.
Key features of HDML include:
- Text-based format: HDML is a simple, text-based language that is easy to read and write. It uses a limited set of tags and attributes to describe the structure and appearance of content on handheld devices.
- Device-specific customization: HDML allows content creators to tailor their content for different devices, taking into account factors such as screen size, color capabilities, and input methods.
- Navigation support: HDML provides built-in support for navigating between cards (individual screens of content) using hyperlinks, menus, and form inputs.
- Limited scripting capabilities: HDML includes a basic scripting language called Handheld Device Transport Protocol (HDTP), which enables simple client-side processing and user interaction.
Despite its early success and adoption, HDML was eventually replaced by Wireless Markup Language (WML) as the standard markup language for mobile devices. WML is part of the Wireless Application Protocol (WAP) suite of technologies, which provides a more comprehensive and standardized framework for delivering content and services to mobile devices.
In summary, Handheld Device Markup Language (HDML) is an early markup language designed for creating content for handheld devices. Although it has since been replaced by more advanced technologies like WML and, eventually, HTML5 for mobile web development, HDML played a crucial role in the early days of mobile web browsing and the development of mobile-specific content.