aqui te dejo un ejemplo:
Código PHP:
Ver original<body>
// .... here some php lins... variables o some functions....
//... maybe some post variables an some new values.... proccessed over post variables....
<script type="text/javascript">
function test(){
document.getElementById("php_code").innerHTML="<?php for($i=0; $i<10; $i++) echo $i; //maybe a function ?>";
}
</script>
<a href="#" style="display:block; color:#000033; font-family:Tahoma; font-size:12px;" onclick="test(); return false;"> test </a>
<span id="php_code"> </span>
</body>
</html>