UPDATED:

CREATED:

Here is the solution from EmacsWiki.

I found it not effective because tidy is too strict to HTML5 and produces too much noise.

I only need validation of missing open/closed html tag(s). Nothing more!

So here is my complete solution:

(defun flymake-html-init () (let* ((temp-file (flymake-init-create-temp-buffer-copy 'flymake-create-temp-inplace)) (local-file (file-relative-name temp-file (file-name-directory buffer-file-name)))) (list "tidy" (list local-file)))) (defun flymake-html-load () (interactive) (when (and (not (null buffer-file-name)) (file-writable-p buffer-file-name)) (set (make-local-variable 'flymake-allowed-file-name-masks) '(("\\.html\\|\\.ctp\\|\\.ftl\\|\\.jsp\\|\\.php\\|\\.erb\\|\\.rhtml" flymake-html-init)) ) (set (make-local-variable 'flymake-err-line-patterns) ;; only validate missing html tags '(("line \\([0-9]+\\) column \\([0-9]+\\) - \\(Warning\\|Error\\): \\(missing <\/[a-z0-9A-Z]+>.*\\|discarding unexpected.*\\)" nil 1 2 4)) ) (flymake-mode t))) (add-hook 'web-mode-hook 'flymake-html-load) (add-hook 'html-mode-hook 'flymake-html-load) (add-hook 'nxml-mode-hook 'flymake-html-load) (add-hook 'php-mode-hook 'flymake-html-load)

The only difference from EmacsWiki is only one line: