<textarea id="txtIn" rows="10" style="width:90%" onchange="onChange()"></textarea> <!--
<br />
<textarea id="txtOut" rows="10" style="width:90%"></textarea>
<br />
<input type="button" onclick="convert();" value="Convert" /> -->
<script>
function escapeHTML (str)
{
var div = document.createElement('div');
var text = document.createTextNode(str);
div.appendChild(text);
return div.innerHTML;
};
function convert()
{
document.getElementById("txtOut").value = escapeHTML(document.getElementById("txtIn").value);
}
function onChange() {
const html = escapeHTML(document.getElementById("txtIn").value);
navigator.clipboard.writeText(html);
}
</script>