Escape Html by Javascript

When I copy and paste some code snippet on this blog, I have to escape some special characters for example "<", ">", etc.
I googled how to escape html special characters by javascript and found escaping-html-strings-with-jquery.

Based on the answer, I created simple html escape tool below.

copy & paste text in this text area, then html escaped text will be output text area below.

The whole javascript code is below!

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script>
$(function(){
$("#src_html").keyup(function(){
$("#dest_html").val(escapeHtml($("#src_html").val()));
});

var entityMap = {
  "&": "&amp;",
  "<": "&lt;",
  ">": "&gt;",
  '"': '&quot;',
  "'": '&#39;',
  "/": '&#x2F;'
};

function escapeHtml(string) {
  return String(string).replace(/[&<>"'\/]/g, function (s) {
    return entityMap[s];
  });
}
});
</script>