function $( obj )
{
	if( document.getElementById )
		return document.getElementById( obj );
	else if( document.all )
		return document.all[ obj ];
	else
		return document.layers[ obj ];
}


function $$( tag )
{
	return document.getElementsByTagName( tag );
}


function $$$( obj, tag )
{
	return obj.getElementsByTagName( tag );
}


function $I( obj )
{
	return document.images[ obj ];
}


function addLoadEvent( func )
{
// Zorg ervoor dat de al aanwezige window.onload functie(s)
// Niet worden overschreven
// Usage:
// addLoadEvent(nameOfSomeFunctionToRunOnPageLoad);
// addLoadEvent(function() {
//  /* Code dat on page load moet worden uitgevoerd. */ 
// });
  var oldonload = window.onload;
  if (typeof window.onload != 'function')
	{
    window.onload = func;
  }
	else
	{
    window.onload = function()
		{
      if (oldonload)
			{
        oldonload();
      }
      func();
    }
  }
}


function getCachePrevent( )
{
	return "&rand=" + escape( Math.round( Math.random( ) * 10000 ) );
}

function Nop( ) { }

function loadingMessage( show )
{
	if( $( 'workingBlock' ) != null )
	{
		if( show )
		{
			$( 'workingBlockText' ).innerHTML = '<img src="../../images/loading.gif" align="absmiddle" /> Bezig...';
			$( 'workingBlock' ).style.display = 'block';
		}
		else
		{
			setTimeout( '$( \'workingBlockText\' ).innerHTML = \'Klaar!\'', 500 );
			setTimeout( '$( \'workingBlock\' ).style.display = \'none\'', 1000 );
		}
	}
}