var Overlay = new Class({
  
  getOptions: function(){
    return {
      colour: '#000',
      opacity: 0.5,
      zIndex: 999,
      container: document.getElementById("overlay"),
      onClick: Class.empty
    };
  },

  initialize: function(options){
    this.setOptions(this.getOptions(), options);
    
    this.options.container = $(this.options.container);
    
    this.container = new Element('div').setProperty('id', 'OverlayContainer').setStyles({
      position: 'fixed',
      left: 0,
      top: 0,
      width: '100%',
      zIndex: this.options.zIndex
    }).injectInside(this.options.container);
    
    this.iframe = new Element('iframe').setProperties({
      'id': 'OverlayIframe',
      'name': 'OverlayIframe',
      'src': 'javascript:void(0);',
      'frameborder': 1,
      'scrolling': 'no'
    }).setStyles({
      'position': 'absolute',
      'top': 0,
      'left': 0,
      'width': '100%',
      'height': '100%',
      'zIndex': 999,
      'filter': 'progid:DXImageTransform.Microsoft.Alpha(style=0,opacity=0)',
      'opacity': 0
    }).injectInside(this.container);
    
    this.overlay = new Element('div').setProperty('id', 'Overlay').setStyles({
      position: 'fixed',
      bottom: 0,
      left: 0,
      right: 0,
      top: 0,
      width: '100%',
      height: '100%',
      zIndex: 999,
      backgroundColor: this.options.colour
    }).injectInside(this.container);
    
    this.container.addEvent('click', function(){
      this.options.onClick();
    }.bind(this));
    
    this.fade = new Fx.Style(this.container, 'opacity').set(0);
    this.position();
    
    window.addEvent('resize', this.position.bind(this));
  },
  
  position: function(){
    if(this.options.container == document.body){ 
      var h = window.getScrollHeight(); 
      this.container.setStyles({top: 0, height: h}); 
    }else{ 
      var myCoords = this.options.container.getCoordinates(); 
      this.container.setStyles({
        bottom: 0,
        left: 0,
        right: 0,
        top: 0,
        width: '100%',
        height: '100%'
      }); 
    } 
  },
  
  show: function(){
    this.fade.start(0,this.options.opacity);
  },
  
  hide: function(){
    this.fade.start(this.options.opacity,0);
  }
  
});
Overlay.implement(new Options);