Check if string is valid html tag.
<p>Is there any Native Javascript Functions to check if html tag exists?</p>

<p>I mean :</p>

<pre><code> var tag = "div";
 alert(isValidTag(tag)) // true;
 alert(isValidTag("foo")) // false;
</code></pre>

<p><em>If there is no native function for that, I will keep my function :</em></p>

<pre><code>function isValidTag(tagName) {
  var tags = ["div","span","a","link" ... "body"];
  for(var i=0, len = tags.length; i++ &lt; len; ) {
    if(tags[i] == tagName) return true;
  }
  return false;
}
</code></pre>
