向 iframe 的主体添加属性在 Chrome 中有效，但在 Firefox 中无效

Question

Does anyone know why this works - that is to say, the attribute is added - in Chrome, but not in Firefox?

this.wrapper.appendChild(this.ifr = document.createElement('iframe'));
this.ifr_doc = this.ifr.contentDocument || this.ifr.document;
this.ifr_doc.documentElement.querySelector('body').setAttribute('foo', 'bar'); //GRR...

No error; it's just in Chrome, in the inspector, the attribute shows up, while in Firefox (v 41.0.2) it doesn't.

( this.wrapper is a container housing the iframe)

Answer 1

try this:

 if (this.ifr_doc.readyState == 'complete') {      
     this.ifr_doc.body.setAttribute('foo', 'bar'); 
 }