var isIE4 = false;
var isNA4 = false;

var imageArray = new Array();

function onLoad()
{
  if ( parseInt(navigator.appVersion) >= 4){
    if (navigator.appName == "Netscape"){
      isNA4 = true;
    }    
    else{
      isIE4 = true; 
    }
  }

  if(document.images){
    imageArray["pfeile_trans"] = new Image();
    imageArray["pfeile_trans"].src = "/img/pfeile_trans.gif";
    imageArray["pfeile_weiss"] = new Image();
    imageArray["pfeile_weiss"].src = "/img/pfeile_weiss.gif";

 }

}

onLoad();

function imgSwap(posName, imgName)
{
  if(document.images){
   
    document[posName].src = imageArray[imgName].src;
    return;
  }
}