// Hide / show an element (e.g. a <div> layer).
function toggle( id ) {
   hideOthers( id );
   
   // Toggle visibility between visible and invisible (i.e. between 'none' and 'inline')
   if (("none" == document.getElementById(id).style.display))
   {
      // show
      //alert( "showing " + id );
      document.getElementById(id).style.display = "inline";
      document[id + "arrow"].src = "images/arrow-down.gif"
   } else {
      // hide
      //alert( "hiding " + id );
      document.getElementById(id).style.display = "none";
      document[id + "arrow"].src = "images/arrow-right.gif";
   }
}

// Hide all abstracts except the one with id == 'me' 
function hideOthers( me ) {
	var tagArray = document.getElementsByTagName( 'span' ); // produces an array of all objects in the page that are the tag you requested
	for (i = 0; i < tagArray.length; i++) {
	    var element = document.getElementById(tagArray[i].id);
		if (element.id != me) {
           element.style.display ="none";
           document[element.id + "arrow"].src = "images/arrow-right.gif";
		}
	}
}