var html = “red red something else redder”;

// should minimally match links (extend to add more tags)
var donotwant=new RegExp(/(<a.*?)/);
// separator will be included in pieces, as we add () in the regexp
var pieces = html.split(donotwant);
for ( var i = 0; i < pieces.length; i++ ) {
var piece = pieces[i];
if ( !donotwant.test(piece) ) {
// do the actual replacement
pieces[i]=piece.replace(’red’,'(red)’);
}
}

// join it back together to get final html
html = pieces.join(”);

Well something like that anyway. A bit more work would be required, but that’s the basic approach.