Graphical authoring and editing of mark-up language sequences

A graphical mark-up language authoring system using drag and drop placement of symbols representing mark-up language elements on a computer screen drawing and connecting the blocks by lines representing data and control flow to create a mark-up language sequence design. The symbols are instances of a mark-up language element that include the properties and attributes of that element. The system also includes a mark-up language view of the elements and their attributes and properties. The system permits effective authoring of mark-up language sequences by users not expert in mark-up language sequence design.