PHP Code:
<script>
function 
lol() {
myFrame.document.open();
myFrame.document.write("LOLOLOLOLOLOLOLOLOLOLOLOLOLOL<br>LOLOLOLOLOL");
myFrame.document.close();
}
</script>

<iframe name="myFrame" id="myFrame" height="700" src ="http://www.google.pt" width="100%"></iframe>

<script>lol();</script> 
The result should be the google's page with the "LOLOLOLOLLO" added at the end(or begining?).