Markup is used to make content readable by mobile browsers. Normally when we think of markup, we think of HTML, or Hypertext Markup Language, the language of the Web. In mobile, we use slightly different markup languages, depending on the scope and size of your project or on your target devices.
Back in 1996, HDML (Handheld Device Markup Language) was created by Openwave, one of the early pioneers of the mobile web. It was quickly followed by Nokia’s TTML (Tagged Text Markup Language) and other proprietary markup languages, before the WAP (Wireless Application Protocol) Forum created the WML (Wireless Markup Language) specification in 1998, which was included in the WAP 1.0 specification.
Many people coming from the Web assume the mobile web works in the same way as and lives on the same protocols the desktop web does, which isn’t the case. WAP is the stack in which the mobile web lives, but it is a protocol unto itself. Saying that WAP and the Web are synonymous would be like saying that men and women are the same. Yes, they are both humans, and technically how they function is very similar to one another, but there are some fundamental and obvious differences. Mobile devices are much more like their desktop computer counterparts today, but there are still many remnants of WAP within the current operator-delivered mobile web.
WML looks more like XML than HTML, using a strict format to mark up content, organized into cards, or pages; therefore an entire WML site would be referred ...