Fastest method to escape HTML tags as HTML entities?

Question

I'm writing a Chrome extension that involves doing a lot of the following job: sanitizing strings that might contain HTML tags, by converting <, > and & to <, > and &, respectively.

(In other words, the same as PHP's htmlspecialchars(str, ENT_NOQUOTES) – I don't think there's any real need to convert double-quote characters.)

This is the fastest function I have found so far:

function safe_tags(str) {
    return str.replace(/&/g,'&amp;').replace(/</g,'&lt;').replace(/>/g,'&gt;') ;
}

But there's still a big lag when I have to run a few thousand strings through it in one go.

Can anyone improve on this? It's mostly for strings between 10 and 150 characters, if that makes a difference.

(One idea I had was not to bother encoding the greater-than sign – would there be any real danger with that?)

Answer 1

Here's one way you can do this:

var escape = document.createElement('textarea');
function escapeHTML(html) {
    escape.textContent = html;
    return escape.innerHTML;
}

function unescapeHTML(html) {
    escape.innerHTML = html;
    return escape.textContent;
}

Here's a demo.