FDML was an extension of HTML that used special tags, such as [FMP-Record][/FMP-Record] to display FileMaker data on Web pages. FDML was known for its ease of use, clear syntax, and speed of development.
FDML was perceived to have some severe limitations in comparison with other middleware languages. For instance, it would only let you use 9 tokens as variables, there was no math support, no repeat loops and no debugger within the language itself (although all of these functions were available within the database).
Due to this different approach, low adoption and emergence of competing tools such as Lasso, FileMaker officially dropped support for FDML in 2004.
In 2007, based on popular demand, FMWebschool created a PHP based version of FDML under the title of Blackbelt.