svgclass.js

(function($){
    var addClass = $.fn.addClass;
    $.fn.addClass = function(value) {
      var orig = addClass.apply(this, arguments);
      
      var elem,
        i = 0,
        len = this.length;
      
      for (; i < len; i++ ) {
        elem = this[ i ];
        if ( elem instanceof SVGElement ) {
          var classes = $(elem).attr('class');
          if ( classes ) {
              var index = classes.search(value);
              if (index === -1) {
                classes = classes + " " + value;
                $(elem).attr('class', classes);
              }
          } else {
            $(elem).attr('class', value);
          }
        }
      }
      return orig;
    };
    
    var removeClass = $.fn.removeClass;
    $.fn.removeClass = function(value) {
      var orig = removeClass.apply(this, arguments);
      
      var elem,
        i = 0,
        len = this.length;
      
      for (; i < len; i++ ) {
        elem = this[ i ];
        if ( elem instanceof SVGElement ) {
          var classes = $(elem).attr('class');
          if ( classes ) {
            var index = classes.search(value);
            if (index !== -1) {
              classes = classes.substring(0, index) + classes.substring((index + value.length), classes.length);
              $(elem).attr('class', classes);
            }
          }
        }
      }
      return orig;
    };
})(jQuery);