I have a couple of questions:

1. Is `<iframe src="/index.php"></iframe>` the same as HTMLIFrameElement ?
2. Why

```
<iframe src="data:text/html;base64,aHR0cDovL2V4YW1wbGUuY29t"
    height=1280 width=800></iframe>

```

works fine, but

```
a=document.getElementsByTagName('body')[0];
b=document.createElement('iframe');
b.src="data:text/html;base64,aHR0cDovL2V4YW1wbGUuY29t";
a.appendChild(b);

```

does not work? I mean in DOM HTMLIFrameElement src I could put function with encoded string. Is it possible to encode string only in src variable?