Detect HTML5 dynamically in vim

Question

This is due to How to update new Vim HTML elements to color code , but I want the syntax highlighting to highlight only elements if it detects html5 doctype in the first line of the file. Is there an easy way to do this?

Answer 1

You would add something like this to the top of the syntax file html.vim:

if getline (1) = ~? '<! DOCTYPE html>'
  let b: html5 = 1
else
  let b: html5 = 0
endif

And then in the syntax file you can use if b:html5to check if html5 is used for the current buffer.

if b: html5
  "new html 5 tags
  syn keyword htmlTagName contained video canvas
endif