iframe inserted by javascript doesn't load in web page

BZZZZ · Unread post by **BZZZZ** » 2021-11-09, 14:19

I have this hosted as html file on local http server:

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8"/>
  <title>iframe javascript test</title>
</head>
<body>
<script type="text/javascript">
{
  let elem;
  if(window===top){
    elem=document.createElement("iframe");
    elem.onload=()=>{
      const elem=document.createElement("h1");
      elem.textContent="iframe loaded";
      document.body.appendChild(elem);
    };
    elem.src=location.href;
  }else{
    elem=document.createElement("h1");
    elem.textContent="inside iframe";
  }
  document.body.appendChild(elem);
}
</script>
</body>
</html>

If I open it in firefox or chromium it shows (not to scale):

Code: Select all

┏━━━━━━━━━━━━━┓
┃inside iframe┃
┗━━━━━━━━━━━━━┛
iframe loaded

If I open it in palemoon it shows (not to scale):

Code: Select all

┏━━━━━━━━━━━━━┓
┃             ┃
┗━━━━━━━━━━━━━┛

Why is it different in palemoon?

Unread post by **Moonchild** » 2021-11-09, 15:18

BZZZZ wrote: ↑
2021-11-09, 14:19
Why is it different in palemoon?

We don't allow iframes to recursively load themselves (which is a known "evil trap")

EDIT: It seems Firefox allows this to satisfy some automated tests (assuming the same goes for Chrome)
I don't particularly see a reason to allow nested iframes with the same URL/location; it's risky.

EDIT2: Firefox allows this because WPT tests expect this. WPT tests expect this allowance because Chromium does. So basically Chromium determines Firefox's behaviour here by way of having "expected" results of what is supposed to be an independent test platform be shaped after Chromium's implementation.
If there was ever a clear indicator that Google controls the reference other browsers are forced to match against, this is it.

Pale Moon forum

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iframe inserted by javascript doesn't load in web page

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