(function(wysihtml5) {
  var api = wysihtml5.dom;
  
  api.addClass = function(element, className) {
    var classList = element.classList;
    if (classList) {
      return classList.add(className);
    }
    if (api.hasClass(element, className)) {
      return;
    }
    element.className += " " + className;
  };
  
  api.removeClass = function(element, className) {
    var classList = element.classList;
    if (classList) {
      return classList.remove(className);
    }
    
    element.className = element.className.replace(new RegExp("(^|\\s+)" + className + "(\\s+|$)"), " ");
  };
  
  api.hasClass = function(element, className) {
    var classList = element.classList;
    if (classList) {
      return classList.contains(className);
    }
    
    var elementClassName = element.className;
    return (elementClassName.length > 0 && (elementClassName == className || new RegExp("(^|\\s)" + className + "(\\s|$)").test(elementClassName)));
  };
})(wysihtml5);
