Iframe source with variable

问题

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?

回答1:

The Data URI scheme is for direct embedded data.

data:text/html;base64,aHR0cDovL2V4YW1wbGUuY29t

Means a html page with "http://example.com" as its sole content.

You probably want "http://example.com" as src

回答2:

1. Yes
2. You need to append the iFrame to the document. Like so document.body.appendChild(b)​

回答3:

To your point 2: your two methods give the same result.

Live demo: http://jsfiddle.net/Ft9gh/

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

来源：https://stackoverflow.com/questions/13958097/iframe-source-with-variable