Untitled

How to use javascript to get html special characters in text input
<script type="text/javascript">
function qpush(a) {
    document.getElementById('input').value += a;
}

function show(a) {
    alert(document.getElementById('input').value);
}
</script>

<input type="text" id="input" />
<input type="button" onclick="qpush('&pi;');" value="&pi;" />
<input type="button" onclick="show()" value="go" />

<button type="button" value="&pi;">π</button>

document.getElementById('input').value.replace(/π/g,"&pi;");