HTML-encoding lost when attribute read from input field

Question

I’m using JavaScript to pull a value out from a hidden field and display it in a textbox. The value in the hidden field is encoded.

For example,

Answer 1

EDIT: This answer was posted a long ago, and the htmlDecode function introduced a XSS vulnerability. It has been modified changing the temporary element from a div to a textarea reducing the XSS chance. But nowadays, I would encourage you to use the DOMParser API as suggested in other anwswer.

---

I use these functions:

function htmlEncode(value){
  // Create a in-memory element, set its inner text (which is automatically encoded)
  // Then grab the encoded contents back out. The element never exists on the DOM.
  return $('').text(value).html();
}

function htmlDecode(value){
  return $('<textarea/>').html(value).text();
}
</code></pre>

<p>Basically a textarea element is created in memory, but it is never appended to the document.</p>

<p>On the <code>htmlEncode</code> function I set the <code>innerText</code> of the element, and retrieve the encoded <code>innerHTML</code>; on the <code>htmlDecode</code> function I set the <code>innerHTML</code> value of the element and the <code>innerText</code> is retrieved.</p>

<p>Check a running example here.</p>
    </p>
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