Function to highlight one or more words in a string

highlight-words.js

function highlight(str, words)
{
	var before = '<strong class="highlight">', beforeLen = before.length,
		after = '</strong>', afterLen = after.length

	if (typeof words == "string")
		words = [words]
	if (words == null || words.length == 0)
		return str

	$.each(words, function(i, w){
		w = $.trim(w).toLowerCase()
		if (w == '')
			return
		var lower = str.toLowerCase(), lowerLen = lower.length,
			wLen = w.length, offset = 0, searchStart = 0
		while(true)
		{
			if (searchStart > lowerLen-1)
				break
			var pos = lower.indexOf(w, searchStart)
			if (pos == -1)
				break
			searchStart = pos + 1
			pos += offset // found position with offset after previous replacements
			str = str.slice(0, pos) + before
				+ str.slice(pos, pos+wLen) + after
				+ str.slice(pos+wLen)
			offset += beforeLen + afterLen
		}
	})

	return str
}