public static function stripHtmlTags(html:String, tags:String = null):String
{
    var tagsToBeKept:Array = new Array();
    if (tags.length > 0)
        tagsToBeKept = tags.split(new RegExp("\\s*,\\s*"));
 
    var tagsToKeep:Array = new Array();
    for (var i:int = 0; i < tagsToBeKept.length; i++)
    {
        if (tagsToBeKept[i] != null && tagsToBeKept[i] != "")
            tagsToKeep.push(tagsToBeKept[i]);
    }
 
    var toBeRemoved:Array = new Array();
    var tagRegExp:RegExp = new RegExp("<([^>\\s]+)(\\s[^>]+)*>", "g");
 
    var foundedStrings:Array = html.match(tagRegExp);
    for (i = 0; i < foundedStrings.length; i++) 
    {
        var tagFlag:Boolean = false;
        if (tagsToKeep != null) 
        {
            for (var j:int = 0; j < tagsToKeep.length; j++)
            {
                var tmpRegExp:RegExp = new RegExp("<\/?" + tagsToKeep[j] + "[^<>]*?>", "i");
                var tmpStr:String = foundedStrings[i] as String;
                if (tmpStr.search(tmpRegExp) != -1) 
                    tagFlag = true;
            }
        }
        if (!tagFlag)
            toBeRemoved.push(foundedStrings[i]);
    }
    for (i = 0; i < toBeRemoved.length; i++) 
    {
        var tmpRE:RegExp = new RegExp("([\+\*\$\/])","g");
        var tmpRemRE:RegExp = new RegExp((toBeRemoved[i] as String).replace(tmpRE, "\\$1"),"g");
        html = html.replace(tmpRemRE, "");
    } 
    return html;
}