Do some browsers contain multiple threads in the operating system?
<p>I'm trying to understand how my code works from a macro perspective.</p>

<p>I've learned that parallel programming is possible from this <a href="http://stackoverflow.com/questions/3897625/parallel-javascript-code">SO Question</a> which links out to an article on <a href="http://ejohn.org/blog/web-workers/" rel="nofollow">web workers</a> by Resig.</p>

<p>I found this confusing because I thought that I had read that JavaScript in the browser is single threaded.</p>

<p>Perhaps I've mis-matched things.</p>

<p>Do some browsers support multi-threading?  Is this similar or correlative to parallel processing?</p>
