window.onload = myonload;

function myonload(){
  layoutSettings();
  textticker();
}

// Layout anpassen
function layoutSettings() {
	contentHeight = document.getElementById("inhalt").offsetHeight;
	minimumContentHeight = 450;
	if(contentHeight < minimumContentHeight) { contentHeight = minimumContentHeight; }
	document.getElementById("navigation").style.height = contentHeight + "px";
}

// Ticker laden
function textticker(){
			document.tickerform.ticker.value = text.substring(1,1000) + text.substring(0, 1);
			text = document.tickerform.ticker.value;
			window.setTimeout("textticker()",300);
			}

<script src="../aktuell.txt"></script>