Placez le BODY:

<body onload="doWave(0)" background="../navigation/fond3.gif" bgcolor="#CCCCCC">
<script language="JavaScript">
var theText = "Texte qui ondule !";
function nextSize(i,incMethod,textLength)
{
if (incMethod == 1) return (72*Math.abs( Math.sin(i/(textLength/3.14))) );
if (incMethod == 2) return (255*Math.abs( Math.cos(i/(textLength/3.14))));
}
function sizeCycle(text,method,dis)
{
output = "";
for (i = 0; i < text.length; i++)
{
size = parseInt(nextSize(i +dis,method,text.length));
output += "<font style='font-size: "+ size +"pt'>" +text.substring(i,i+1)+ "</font>";
}
theDiv.innerHTML = output;
}
function doWave(n)
{
sizeCycle(theText,1,n);
if (n > theText.length) {n=0}
setTimeout("doWave(" + (n+1) + ")", 50);
}
</script>
<div id="theDiv" align="center">