Detect version of JavaScript

Question

How can I detect what version of JavaScript the browser supports (if any)? I want to check for ECMAScript 3 versus ECMAScript 5 versus ECMAScript 6.

Note: I want to avoid the deprecated language tag.

Answer 1

Here is a good reference for you: http://www.docsteve.com/DocSteve/Samples/JS/js_version.html

Basically, use the deprecated language attribute of the script tag

console.log("javascript version =", js_version)

<script language="javascript">var js_version="1.0"</script>
<script language="javascript1.1">var js_version="1.1"</script>
<script language="javascript1.2">var js_version="1.2"</script>
<script language="javascript1.3">var js_version="1.3"</script>
<script language="javascript1.4">var js_version="1.4"</script>
<script language="javascript1.5">var js_version="1.5"</script>
<script language="javascript1.6">var js_version="1.6"</script>

Answer 2

The solution proposed to http://www.docsteve.com/DocSteve/Samples/JS/js_version.html as simple JavaScript function (using "createElement" construction):

<script type="text/javascript">
  function get_js_version ()
  {
    this.jsv = {
        versions: [
          "1.1", "1.2", "1.3", "1.4", "1.5", "1.6", "1.7", "1.8", "1.9", "2.0"
        ],
        version: ""
      };

    var d = document;

    for (i = 0; i < jsv.versions.length; i++) {
      var g = d.createElement('script'),
        s = d.getElementsByTagName('script')[0];

        g.setAttribute("language", "JavaScript" + jsv.versions[i]);
        g.text = "this.jsv.version='" + jsv.versions[i] + "';";
        s.parentNode.insertBefore(g, s);
    }

    return jsv.version;
  }

  document.write('JavaScript Version: ' + get_js_version());
</script>

Answer 3

This pops out an alert box with the javascript version being used by your browser:

<script type="text/javascript">
  var jsver = 1.0;
</script>
<script language="Javascript1.1">
  jsver = 1.1;
</script>
<script language="Javascript1.2">
  jsver = 1.2;
</script>
<script language="Javascript1.3">
  jsver = 1.3;
</script>
<script language="Javascript1.4">
  jsver = 1.4;
</script>
<script language="Javascript1.5">
  jsver = 1.5;
</script>
<script language="Javascript1.6">
  jsver = 1.6;
</script>
<script language="Javascript1.7">
  jsver = 1.7;
</script>
<script language="Javascript1.8">
  jsver = 1.8;
</script>
<script language="Javascript1.9">
  jsver = 1.9;
</script>


<script type="text/javascript">
  alert(jsver);
</script>

Related jsfiddle.net