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 */
}

```
Wouldn't it be unhidden in the first place if your css isn't setting it to display: none; ?

If you want to hide it or show it you should just be able to use some JQuery:

```
$(document.body).css( "display", "none" );

```

or

```
$(myForm.elements).hide()

```

And so on.