Expander = Behavior.create({
  initialize : function(long_selector, short_selector, hideShortContent){
    if(hideShortContent==null) hideShortContent = true;
    this.hideShortContent=hideShortContent;
    this.longTags = $$(long_selector);
    this.shortTags = $$(short_selector);
    this.contentId = this.element.href.split("#")[1];
    this.longContent = $(this.contentId);
    this.shortContent = $(this.contentId + '_short')
  },
  onclick : function(event){
    event.preventDefault();
    this.longTags.each(function(elem) { elem.hide() })
    this.shortTags.each(function(elem) { elem.show() })
    this.longContent.toggle();
    if(this.hideShortContent) this.shortContent.toggle();
    this.element.toggleClassName('expanded')
    this.element.innerHTML = (this.element.innerHTML == 'more...') ? 'less...' : 'more...'
  }
});