chrome helper ExecuteJavascriptResult

[Peter.Wayne]

I need to take a certain action depending on whether a certain class is present in a web page. No, I didn't write the web page, it's a web site I am accessing and trying to navigate through it programmatically.
Here is one line of Xbasic using the chrome helper:
cp.ExecuteJavascript("const collection=document.getElementsByClassName('theClassInQuestion')")
Now, what I want to do is see the size of the class, by trying
collectionSize=cp.ExecuteJavascriptResult("collection.length")
if collectionSize>0 then
something
else
somethingElse
end if
But cp.ExecuteJavascriptResult doesn't seem to be returning the collection length. How does on use the ExecuteJavascriptResult to get the result back into Xbasic?

[Ted Giles]

What does the command actually return?

[Peter.Wayne]

Thanks for your interest. What I've discovered is that the command is working; the problem I run into is that the commands seem to run before the chrome helper has fully loaded the page. So the command usually returns a 0, even
when it should return a 1. I've been experimenting with throwing in a few sleep(1) statements at different points in the code to give the chrome helper time to "see" the DOM, and then sometimes I get a 1 like I should. I'll keep experimenting
with throwing in speed bumps.

[Mike Wilson]

Hi Peter,
I have experienced the need for a code pause in order for things to execute throughout my Alpha journey. What I developed is a UDF that calls an xdialog that opens and closes within a very short period of time. I have had good success with it when sleep() and xbasic_wait_for_idle() don't work. Maybe it will help in your circumstance.

FUNCTION dlg_blink AS C ( )

'xdlg to get code to slow
ui_dlg_box("blink",<<%dlg%
{nocaption}{position=11,11}{timer=rotate}{interval=.2}{lf};
%dlg%,<<%code%
if a_dlg_button="rotate" then
ui_modeless_dlg_close("blink")
end if
%code%)

END FUNCTION
dlg_blink()​

[madtowng]

I'm no expert but maybe a setTimeout() function will help solve the problem.

[jhackney]

Peter, did you ever resolve your problem? I ask because I am about to submit a similar question to the board. I had your issue or a similar issue a long time ago and my work around was the following:

jstorun = "Whatever"
myVar = cp.ExecuteJavascriptResult(jstorun)  'this does not work
myVar = cp.ExecuteJavascriptResult(jstorun)  'Now it works

Another favorite of mine which is not recommended is as follows:

cp.ExecuteJavascript(obj = 'Whatever')
cp.ExecuteJavascript(window.myWhateverObj = obj)

jstorun = "window.myWhateverObj"
myStr = cp.ExecuteJavascriptResult(jstorun)

dim myP as P
myP.dummy = ""
property_from_string(myP, myStr)​
​

I am currently stuck on another unrelated issue that has me concerned that the chrome control does not work consistently on larger HTML documents. I would like to know if your application hangs several seconds up to ten seconds when you call the cp.ExecuteJavascriptResult command.