Question: How can I check if textarea is hidden using javascript?

Answer: 
```
var textArea = document.getElementById('textAreaId');

if (textArea.currentStyle.visibility === 'hidden' || textArea.currentStyle.display === 'none')
{
   /* code */
}

```
Did you try elm.getBoundingClientRect() ?

It will give all zero values if the element or a parent has display:none.  

With visibility:hidden the element is there and then has a boudning rectangle.

```
<html>
<head>
    <title>hidden</title>
</head>
<body>
<div style="display:none">
    <form>
        <textarea></textarea>
    </form>
</div>
<script>
  var rect = document.getElementsByTagName('TEXTAREA')[0].getBoundingClientRect();
  alert(rect.right === 0 ? 'hidden':'visible');
</script>
</body>
</html>

```