I have a button in html called btnS: 

```
<button type="submit" id="btnS" class="hide" value="button">Send</button>

```

That I disabled with dom via external script dom:

```
btnS.setAttribute('disabled', 'false');

```

I tried to get it "back on" again via:

```
btnS.setAttribute('enabled', 'true');

```

But that didn't work? The button was first invisible via a css rule:

```
.hide {
    visibility : hidden;
}

```

And I changed that as well before with :

```
btnS.setAttribute('class', 'show');     

```

Rule:

```
.show {     visibility:visible; }

```