[Edbrowse-dev] immediate evaluation of js on appendChild

[Edbrowse-dev] immediate evaluation of js on appendChild

[Kevin Carhart]

Suppose a site author has a piece of javascript stored in the .text 
property of a script element.  It's only a string.  But now controlling JS 
code runs appendChild of that script element.  Possibly insertBefore too.
Now that javascript code is part of the DOM.  I think this code is 
supposed to evaluate immediately.  Does this ring a bell and if it's 
something that should happen but currently doesn't, what would be an 
appropriate place to implement it?
Maybe it could be done directly in startwindow.js, because side effects 
from the code in question will be dealt with as the chunk of JS is itself 
addressed line by line and the JS functions trigger the existing side 
effects code.  eval() comes to mind though I think it is considered 
harmful.

thanks
Kevin

Re: [Edbrowse-dev] immediate evaluation of js on appendChild

[Kevin Carhart]

Hi Karl
Yes.... could you go to http://carhart.net/~kevin/immediate.html?
In edbrowse nothing will happen so please 'ub' for the HTML source.
Now if I bail out and try it in my firefox, 
the alert will fire.  I'm not sure precisely which line it occurs on.  But 
there is not an eval() in javascript, so I think there must be evaluation 
supplied by the DOM.

I believe this is the purpose of the iframe formulation in the google 
groups page we were talking about a while ago.  immediate.html is a 
simpler version of the construction that they use.  Since google is doing 
it, it may be a common phrasing.  Question for Steven Terpe if you're 
around: I think you said you recognized the phrasing
frame.contentDocument.open();
frame.contentDocument.write(html);
frame.contentDocument.close();
Do you know if this is used a lot?

thanks
Kevin



On Wed, 15 Jun 2016, Karl Dahlke wrote:

> Is there some simple js you could whip up and post,
> as an example, so I know what you're talking about?
>
> Karl Dahlke
>

--------
Kevin Carhart * 415 225 5306 * The Ten Ninety Nihilists

[Edbrowse-dev] immediate evaluation of js on appendChild

[Karl Dahlke]

> frame.contentDocument.write(html);

The key here is, I think, when we design the new Iframe object,
that Iframe.contentDocument.write() somehow invokes the innerHTML machinery.
That parses and executes html immediately,
though if that html has <script> as in your example,
the script might not run immediately, as another script is already running,
but I don't think that's a problem,
as long as the html dom objects are created immediately, which they are,
because innerHTML requires that as we already saw.
If my life crises abbate I'll work on this,
because I can see it really needs to be done,
and meantime I'll just advise on the design.

Kevin thanks for uncovering this.
I really think missing dom pieces and interactions are 90% of our
webpage troubles, while the really hard asynchronous ajax java methods etc
are only a small percentage of our troubles.
So filling in missing dom pieces, like Iframe, is probably
the biggest bang for the buck.

Karl Dahlke

Re: [Edbrowse-dev] immediate evaluation of js on appendChild

[Kevin Carhart]

Hi Karl

> If my life crises abbate

I hope they do.  Here's to better times.

> Kevin thanks for uncovering this.

You are welcome!  It's good that the users have been
submitting problems, because this got me rolling and
now I have the itch to get something out the door.
I have found a few different corrections which I need to
write up and submit.

> The key here is, I think, when we design the new Iframe object,
> that Iframe.contentDocument.write() somehow invokes the innerHTML
> machinery.

Aha!  That makes sense.  Hook into the existing innerHTML
machinery and take advantage of it.

Kevin