// functie om een beginwaarde in een veld te laten verdwijnen wanneer het veld aangeklikt wordt.
// wanneer een ander element wordt aan geklikt en het veld is niet ingevuld, wordt de beginwaarde teruggezet. 
// syntax: onFocus=checkValue ( this, 'beginwaarde' ) onBlur=checkValue ( this, 'beginwaarde' )
function checkValue( _element, _value ) {
    if( _element.value == _value ) 
    {   _element.value = "";
        _element.style.color = "#000000";
    }
    else if( _element.value == "" )
    { _element.value = _value;
        _element.style.color = "";  
    }
}

function showHideVisual (){
    var lObject = document.getElementById('visualGroot');
    if (lObject.style.visibility=='visible'){
        lObject.style.visibility='hidden';
    }
    else {
        lObject.style.visibility='visible';
    }
}

function MM_reloadPage(init) {  //reloads the window if Nav4 resized
  if (init==true) with (navigator) {if ((appName=="Netscape")&&(parseInt(appVersion)==4)) {
    document.MM_pgW=innerWidth; document.MM_pgH=innerHeight; onresize=MM_reloadPage; }}
  else if (innerWidth!=document.MM_pgW || innerHeight!=document.MM_pgH) location.reload();
}
MM_reloadPage(true);

// This variable is used in the launchwin function and must be global as of the 
// setTimout function will call this variable after the function has returned.
var newwin;

function  launchwin(winurl,winname)
{
  var winfeatures;
  winfeatures='toolbar=yes,status=yes,menubar=yes,location=yes,resizable=yes,scrollbars=yes';
  //width=' + (screen.availwidth - 10) + ',height=' + (screen.availheight - 80)
  //This launches a new window and  then focuses it if window.focus() is supported.
  newwin = window.open(winurl,winname,winfeatures);
  //delay a bit here because IE4 encounters errors when  trying to focus a recently opened window
  setTimeout('newwin.focus();',250);
}