HtmlSpecialChars equivalent in Javascript?

Bart van Heukelom picture Bart van Heukelom · Nov 24, 2009 · Viewed 193.9k times · Source

Apparently, this is harder to find than I thought it would be. And it even is so simple...

Is there a function equivalent to PHP's htmlspecialchars built into Javascript? I know it's fairly easy to implement that yourself, but using a built-in function, if available, is just nicer.

For those unfamiliar with PHP, htmlspecialchars translates stuff like <htmltag/> into &lt;htmltag/&gt;

I know that escape() and encodeURI() do not work this way.

Answer

Kip picture Kip · Jan 29, 2011

There is a problem with your solution code--it will only escape the first occurrence of each special character. For example:

escapeHtml('Kip\'s <b>evil</b> "test" code\'s here');
Actual:   Kip&#039;s &lt;b&gt;evil</b> &quot;test" code's here
Expected: Kip&#039;s &lt;b&gt;evil&lt;/b&gt; &quot;test&quot; code&#039;s here

Here is code that works properly:

function escapeHtml(text) {
  return text
      .replace(/&/g, "&amp;")
      .replace(/</g, "&lt;")
      .replace(/>/g, "&gt;")
      .replace(/"/g, "&quot;")
      .replace(/'/g, "&#039;");
}

Update

The following code will produce identical results to the above, but it performs better, particularly on large blocks of text (thanks jbo5112).

function escapeHtml(text) {
  var map = {
    '&': '&amp;',
    '<': '&lt;',
    '>': '&gt;',
    '"': '&quot;',
    "'": '&#039;'
  };
  
  return text.replace(/[&<>"']/g, function(m) { return map[m]; });
}