var Class = {
  create: function() {
    return function() {
      this.initialize.apply(this, arguments);
    }
  }
}

var common = {

    hide : function(id) 
    {
	    //safe function to hide an element with a specified id
	    if (document.getElementById) 
	    { // DOM3 = IE5, NS6
		    document.getElementById(id).style.display = 'none';
	    }
	    else 
	    {
		    if (document.layers) 
		    { // Netscape 4
			    document.id.display = 'none';
		    }
		    else 
		    { // IE 4
			    document.all.id.style.display = 'none';
		    }
	    }
    },

    show :  function(id) 
    {
	    //safe function to show an element with a specified id    		  
	    if (document.getElementById) 
	    { // DOM3 = IE5, NS6
		    document.getElementById(id).style.display = 'block';
	    }
	    else 
	    {
		    if (document.layers) 
		    { // Netscape 4
			    document.id.display = 'block';
		    }
		    else 
		    { // IE 4
			    document.all.id.style.display = 'block';
		    }
	    }
    }
};