Changing text link

1

i have three buttons that when clicked are suppose to change the image name in my flash embe code but they dont.
How can i do this?


<title>jstest</title>

<SCRIPT LANGUAGE="JavaScript">
function btn1() {
  document.all("ONE").innerText = 'Bluehills.jpg';
 }
 function btn2() {
  document.all("ONE").innerText = 'Sunset.jpg';
 }
 function btn3() {
  document.all("ONE").innerText = 'Waterlilies.jpg';
 }

 </SCRIPT>
</head>
<body bgcolor="#ffffff">

<OBJECT classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/" WIDTH="250" HEIGHT="300" id="jstest">
  <PARAM NAME=movie VALUE="flash/jstest.swf?imageFilename=images/' + imageFilename +' "> 
    <param name="movie" value="jstest.swf" />
    <param name="quality" value="high" />
    <param name="bgcolor" value="#ffffff" />
  <EMBED src="flash/jstest.swf?imageFilename=images/' + imageFilename +' " quality="high" bgcolor="#FFFFFF" WIDTH="550" HEIGHT="400" NAME="jstest" TYPE="application/x-shockwave-flash" PLUGINSPAGE="http://www.macromedia.com/go/getflashplayer">
  </EMBED>
</OBJECT><br>

<a href="javascript:btn1();">button 1</a> | <a href="javascript:btn2();">button 2</a> | <a href="javascript:btn3();">button 3</a><br />

</body>
</html>