Modify jQuery Highlight? Javascript Regex

How can I modify jquery highlight such that it doesn't find matches that appear directly before or after an alpha character? In other words, how do I prevent a match mid-word?

/*

highlight v3

Highlights arbitrary terms.

<http://johannburkard.de/blog/programming/javascript/highlight-javascript-text-higlighting-jquery-plugin.html>

MIT license.

Johann Burkard
<http://johannburkard.de>
<mailto:jb@eaio.com>

*/

jQuery.fn.highlight = function(pat) {
 function innerHighlight(node, pat) {
  var skip = 0;
  if (node.nodeType == 3) {
   var pos = node.data.toUpperCase().indexOf(pat);
   if (pos >= 0) {
    var spannode = document.createElement('span');
    spannode.className = 'highlight';
    var middlebit = node.splitText(pos);
    var endbit = middlebit.splitText(pat.length);
    var middleclone = middlebit.cloneNode(true);
    spannode.appendChil开发者_高级运维d(middleclone);
    middlebit.parentNode.replaceChild(spannode, middlebit);
    skip = 1;
   }
  }
  else if (node.nodeType == 1 && node.childNodes && !/(script|style)/i.test(node.tagName)) {
   for (var i = 0; i < node.childNodes.length; ++i) {
    i += innerHighlight(node.childNodes[i], pat);
   }
  }
  return skip;
 }
 return this.each(function() {
  innerHighlight(this, pat.toUpperCase());
 });
};

jQuery.fn.removeHighlight = function() {
 return this.find("span.highlight").each(function() {
  this.parentNode.firstChild.nodeName;
  with (this.parentNode) {
   replaceChild(this.firstChild, this);
   normalize();
  }
 }).end();
};

Correct me if I'm wrong, but I think we're focusing on the lines:

var pos = node.data.toUpperCase().indexOf(pat);

And:

 else if (node.nodeType == 1 && node.childNodes && !/(script|style)/i.test(node.tagName)) {

var pos = node.data.toUpperCase().indexOf(pat);

The indexOf method takes a string, and not a regex, as its argument. So you cannot search for whole words using that. You can construct a regex from pat and use String::search() method to search for whole word occurrence of it.

var reg:RegExp = new RegExp("\\b" + pat + "\\b");
var pos = node.data.toUpperCase().search(reg);

If you want to match only whole words, use word boundary \b around the words.

/\b(script|style)\b/i