(I'm assuming you're running JavaScript in the browser, since you're dealing with HTML.)
Rather than trying to use regular expressions to parse HTML (which is generally a bad idea), you're probably better off actually building the DOM tree and then traversing it to get the content you need.
For instance, you can put that table in a disconnected div:
var div = document.createElement('div');
div.innerHTML = your_html_string;
...and then use the DOM methods (and possibly innerHTML) and/or a library to get the content you need.
References:
If you're going to be doing a lot of work in JavaScript on the browser, I recommend using a good JavaScript library like jQuery, Prototype, YUI, Closure, or any of several others. These smooth over browser differences for you and provide a lot of utility functionality so you can focus on the problem at hand.
trthat follows thetr class="high"?