function _addCSSRule(sSelector, sRule){
            var elStyle = htVar.elStyle;

            if(elStyle.addRule){ // Chrome, IE
                elStyle.addRule(sSelector, sRule);
            } else if(htVar.elStyle.insertRule){ // Firefox
                elStyle.insertRule(sSelector + ' { ' + sRule + ' }', elStyle.cssRules.length);
            }
        }
@param {String} sSelector
@param {String} sRule