swipe detector

 var swipeFunc = function() {
  this._swipe_direction = ['left','right'];
  this._y_diff = -1;
  this._x_diff = -1;
  this._x_min_length = 30;
  this.touches = {
    'touchstart': {'entered':false,'x':-1, 'y':-1},
    'touchmove' : {'entered':false,'x':-1, 'y':-1},
    'touchend'  : false,
    'direction' : 'undetermined'
  };
};
swipeFunc.prototype = {
  touchHandler: function(event) {
    var event_handle = this.handle, touch;
    if(typeof event !== 'undefined'){
      event.preventDefault();
      if(event.touches !== 'undefined'){
        touch = event.touches[0];
        switch (event.type) {
          case 'touchstart':
          case 'touchmove':
            event_handle.touches[event.type].entered = true;
            event_handle.touches[event.type].x = touch.pageX;
            event_handle.touches[event.type].y = touch.pageY;
            break;
          case 'touchend':
            event_handle.touches[event.type] = true;
            if(!event_handle.touches.touchmove.entered)
              break;
            event_handle._y_diff = event_handle.touches.touchstart.y > event_handle.touches.touchmove.y ? event_handle.touches.touchstart.y - event_handle.touches.touchmove.y : event_handle.touches.touchmove.y - event_handle.touches.touchstart.y;
            event_handle._x_diff = event_handle.touches.touchstart.x > event_handle.touches.touchmove.x ? event_handle.touches.touchstart.x - event_handle.touches.touchmove.x : event_handle.touches.touchmove.x - event_handle.touches.touchstart.x;
            if (event_handle.touches.touchstart.x > -1 && event_handle.touches.touchmove.x > -1 && event_handle._x_diff > event_handle._x_length_sensitivity && event_handle._x_diff >= event_handle._y_diff) {
              event_handle.touches.direction = event_handle.touches.touchstart.x < event_handle.touches.touchmove.x ? 'right' : 'left';

              // DO STUFF HERE
              //alert(event_handle.touches.direction);

              // checking the swipe direction example:
              for(var k in event_handle._swipe_direction){
                if(event_handle.touches.direction == event_handle._swipe_direction[k])
                  alert(event_handle.touches.direction);
              }
            }
          default:
            break;
        }
      }
    }
  },
  init: function(opts) {
    this._swipe_direction = opts.swipe_dir !== undefined ? opts.swipe_dir : this._swipe_direction;
    this._x_min_length = opts.x_min_length !== undefined ? opts.x_min_length : this._x_min_length;
    document.getElementsByClassName(opts.main_target)[0].addEventListener('touchstart', this.touchHandler, false); 
    document.getElementsByClassName(opts.main_target)[0].addEventListener('touchmove', this.touchHandler, false); 
    document.getElementsByClassName(opts.main_target)[0].addEventListener('touchend', this.touchHandler, false); 
    document.getElementsByClassName(opts.main_target)[0].handle = this;
  }
};
var swipeFunc_1 = new swipeFunc(), swipeFunc_2 = new swipeFunc();
// default left/right swipe detection
swipeFunc_1.init({
  main_target:'class_name_of_target1'
});
// catch only left swiping, with adjustable minimum swipe length
swipeFunc_2.init({
  main_target:'class_name_of_target2',
  swipe_dir: ['left'],
  x_min_length: 40
});