From WHATWG Wiki

Contents 1 vim 1.1 Install 1.2 Usage 1.2.1 Javascript unpacker and beautifier 2 Emacs 2.1 XHTML5 or polyglot documents

vim

vim natively ships with CSS, Javascript & HTML syntax highlighting provided the feature is switched on.

vim also has completion features documented at http://vimdoc.sourceforge.net/htmldoc/insert.html#ft-css-omni

Install

After installing Pathogen to easily manipulate vim's runtimepath.

    cd ~/.vim/bundle; git clone https://github.com/kaihendry/vim-html5

Usage

• Using `:make` whilst editing HTML will upload your HTML buffer to http://validator.nu
• Using `:make` whilst editing Javascript will upload your Javascript buffer to http://jslint.dabase.com

Javascript unpacker and beautifier

Drop it into ~/.vim/ftplugin/javascript/jsbeautify.vim from http://www.vim.org/scripts/script.php?script_id=2727

To run the beautifier, employ the keystrokes [\]+[f]+[f].

Emacs

XHTML5 or polyglot documents

Emacs ships with nxml-mode, a major mode for editing XML which does on-the-fly validation with RELAX NG schema. You can plug fantasai and hsivonen's schema into nxml-mode. The necessary shim code is included in the hober/html5-el project on github.