highlight for node.js is based on highlight.js parser and is meant to highlight code syntax in languages that are not known beforehand (highlight.js detects the used language automatically). This is especially important for pages in Markdown format - there's no easy way to know which language is actually used.
Use npm package manager
npm install highlight
Include syntax highlighter
var hl = require("highlight").Highlight;
highlight code
html = hl("for(var i=0;i<10;i++)alert(i);");
use special tab replacing string (default is 4 spaces)
html = hl(code_string, "<span> </span>");
convert code only between <code> blocks (leaves everything else as is) - especially useful if used together with converted Markdown syntax that includes <code> blocks.
html = hl("<p>PHP:</p><code><?php echo 'Hello world!';?></code>", false, true);
highlight outputs HTML code with predefined CSS class names for different elements. This doesn't make a lot of sense by default (it's just a bunch of SPAN's) so you need to use a CSS file that sets the used color set for the highlighting. There's some sample CSS files in /lib/vendor/highlight.js/styles that can be used with no modification - just include one of the files in the page you are showing the highlighted code.
<link rel="stylesheet" href="/path/to/styles/default.css"/>