Find an object in a window

[Andrew Poulos]

I'm working with some Learning Management Systems (LMS) that provide
elearning to students. The communication between the LMS and the
elearning is down via a js object the LMS call "API".

Now I've know that some LMS will open the elearning in a new window and
embed API in a "hidden" iframe in the window. Some LMS will open the
elearning in a new window and embed API in the window's opener. Some LMS
will open the elearning in a frame within a frameset and embed API in a
"hidden" frame.

A quick look online shows me that other LMS may also embed API in other
locations.

I tried writing a recursive function (that sits in the elearning page)
that searched all frames in the elearning's top window and in the top
window of any opener which appears to work:

function findAPI(win) {
if (win.API) {
return win.API;
}

for (var i = 0; i < win.frames.length; i++) {
if (win.frames[i].API) {
return findAPI(win.frames[i]);
}
}

if (win.opener && !win.opener.closed) {
return findAPI(win.opener.top);
}
}

function fLook() {
var foundApi = findAPI(window.top);
window.alert(foundApi);
}

Any ideas on how to make this (more) robust? For example, its not
checking nested frames.

Andrew Poulos

[Thomas 'PointedEars' Lahn]

Andrew Poulos wrote:

> I tried writing a recursive function (that sits in the elearning page)
> that searched all frames in the elearning's top window and in the top
> window of any opener which appears to work:
>
> function findAPI(win) {
> if (win.API) {
> return win.API;
> }
>
> for (var i = 0; i < win.frames.length; i++) {

var api = findAPI(win.frames[i]);
if (api) {
return api;

> }
> }
>
> if (win.opener && !win.opener.closed) {
> return findAPI(win.opener.top);
> }
> }
>
> function fLook() {
> var foundApi = findAPI(window.top);
> window.alert(foundApi);
> }
>
> Any ideas on how to make this (more) robust? For example, its not
> checking nested frames.

Now it does.

--
PointedEars

Twitter: @PointedEars2
Please do not Cc: me. / Bitte keine Kopien per E-Mail.

[Andrew Poulos]

On 16/05/2013 7:12 PM, Thomas 'PointedEars' Lahn wrote:
> Andrew Poulos wrote:
>
>> I tried writing a recursive function (that sits in the elearning page)
>> that searched all frames in the elearning's top window and in the top
>> window of any opener which appears to work:
>>
>> function findAPI(win) {
>> if (win.API) {
>> return win.API;
>> }
>>
>> for (var i = 0; i < win.frames.length; i++) {
> var api = findAPI(win.frames[i]);
> if (api) {
> return api;
>> }
>> }
>>
>> if (win.opener && !win.opener.closed) {
>> return findAPI(win.opener.top);
>> }
>> }
>>
>> function fLook() {
>> var foundApi = findAPI(window.top);
>> window.alert(foundApi);
>> }
>>
>> Any ideas on how to make this (more) robust? For example, its not
>> checking nested frames.
>
> Now it does.

Too easy! Thanks for the help.

Andrew Poulos

[Thomas 'PointedEars' Lahn]

You're welcome. An omission and a further suggestion on my part, though.

The omission:

for (var i = 0, len = win.frames.length; i < len; i++)

is more efficient than

for (var i = 0; i < win.frames.length; i++)

and as safe if you can be sure that the number of items does not change
while looping. For that matter, if you stored the value of “win.frames” in
a variable and access that variable instead, it would be even more
efficient:

for (var i = 0, frames = win.frames, len = frames.length;
i < len; i++)
{
var api = findAPI(frames[i]);
if (api) {
return api;
}
}

Or you might want to wrap it as suggested e. g. in
<http://naildrivin5.com/blog/2013/05/17/source-code-typography.html?utm_content=buffer5f552&utm_source=buffer&utm_medium=twitter&utm_campaign=Buffer>
(from David Bryant Copeland [@davetron5000 at Github], by tweet of
@kevinSuttle):

for (var i = 0,
frames = win.frames,
len = frames.length;
i < len; i++)
{
var api = findAPI(frames[i]);
if (api) {
return api;
}
}


The suggestion: _it's_ _e-learning_ :)

[Andrew Poulos]

If the number of frames is, say, 10 or less would it make a noticeable
difference from the first way or are you promoting a generally better
approach?

Andrew Poulos