I have a form using Tinymce, I need to check if it only contains space.

I try using this function

```
function validation_form()
{
    var content = tinyMCE.get('main-comment').getContent().replace('&nbsp;','');
    if(content == "" || content == null || content == '<p> </p>') {
        return false;
    }
}

```

But it returns **true** when I input several spaces and submit, I want it to return false instead.

Can anyone help me?
Thanks,