Just threw this together and believe it should work...
<a href="javascript:download();">Download pdf</a>
<div id='link'></div>
<script>
i = 6;
j = 0;
function showLink()
{
i--;
if(i == 0)
{
document.getElementById("link").innerHTML = "<a href='#'>Whatever</a>";
clearInterval(j);
}
else
{
document.getElementById("link").innerHTML = "Please wait for " + i + " seconds";
}
}
function download(){
j = setInterval(showLink, 1000);
}
</script>