Sorty.js

// usage: var mytable = new Sorty(table);

(function(){
  var Row = function(el) {
    this.values = $.map($(el).find('td'), function(e) {
      var el = $(e);
      var attr = el.attr('data-sort');
      return attr ? parseFloat(attr) : el.text();
    });
    this.el = $(el);
  };

  Row.prototype.value = function(i){
    return this.values[i];
  };

  Row.prototype.get = function(){
    return this.el;
  };

  var Sorty = window.Sorty = function(el){
    this.el = $(el);
    this.rows = $.map(this.el.find('tbody tr'), function(el){
      return new Row(el);
    });
    this.orders = [];
    this.body = this.el.find('tbody');
    this.headers = this.el.find('thead tr:last-child th');
    this.headers.on('click', _.bind(this.click, this));
  };

  Sorty.prototype.sort = function(by){
    if(this.orders[by]) {
      this.orders[by] *= -1;
    } else {
      this.orders[by] = -1;
    }

    var order = this.orders[by], ret = [];
    var sorted = this.rows.sort(function(a, b) {
      return (a.values[by] < b.values[by] ? 1 : -1) * order;
    });
    var l = sorted.length;

    for(var i = 0; i < l; i++)
      ret.push(this.rows[i].get());

    return ret;
  };

  Sorty.prototype.click = function(e){
    var cur = $(e.currentTarget);
    var idx = this.headers.index(cur);
    this.body.html(this.sort(idx));
    this.headers.removeClass("sortyUp sortyDown");
    if (this.orders[idx] == -1)
      cur.addClass("sortyUp");
    else
      cur.addClass("sortyDown");
  };
})();