Etwas optimierter:
<html>
<head>
<script language="javascript">
<!--
var b=false;
function set_text(id,txt) {
if(b=!b) document.getElementById(id).innerHTML=" ";
else document.getElementById(id).innerHTML=txt;
}
function blink_text(id,txt,delay) {
setInterval("set_text('"+id+"','"+txt+"')",delay);
}
//-->
</script>
</head>
<body onLoad="blink_text('mytxt','Test',500)">
<div id="mytxt">Test</div>
</body>
</html>
