To call a js-function from VFP, you must always pass at least one parameter. That's a change from older versions of JS. https://west-wind.com/wconnect/weblog/ShowEntry.blog?id=912

Try this instead:

oBrowser.Document.parentWindow.my_js_function(.F.)
or
oBrowser.Document.Script.my_js_function(.F.)

>It is not that straightforward, InvokeScript convenience method for .Net, it is not exposed when IE ActiveX is used in Foxpro.
>something like
>oBrowser.Navigate("my_html_file_with_js.html" )
>oBrowser.Document.parentWindow.my_js_function()
>or
> oBrowser.Document.Script.my_js_function()
>is not working anymore.
>It seemed to work in 2008 :)
>https://weblog.west-wind.com/posts/2008/sep/27/calling-javascript-functions-in-the-web-browser-control
>
>
>>Yes, nearly identical, as IE is activeX. Did a lot of that last century when IE was dominant, but today more and more devs want to escape IE problems. Also I found newer versions of IE to be less stable as activeX components than in IE4-IE6 times, but that might be a misperception as back then I spent much more time roboting WebBrowser and InternetExplorer.Application.
>>
>>Unless your need is a short time temp solution, implement with different tool set.
>>
>>>Can I do something similar to Windows Forms and its Web Browser Control in Foxpro form with its Internet Explorer control.
>>>C# line of code
>>>

>>>  webBrowser1.Document.InvokeScript("openPdfAsBase64", new[] { asBase64 });
>>>