How to capture clicks on links in HTMLViewer

Targets Web
#1

I’m trying to write my first Web app with Xojo. It’ll be a port of a working Desktop app.

I need to render some custom html in a window and need to react to clicks to links inside that html view, in order to update other controls in my window, or alter the html.

I am using a HTMLViewer control and call LoadPage to load my html code.

But I cannot find any event that lets me capture clicks on the links so that I can react to them.

How does one do that? Could I set the hrefs to some address that calls back to my app, perhaps?

Or does MBS offer something for that, like it does in desktop apps? I suspect there are no plugins for Web though, right?

#2

This sounds like use for WebSDK.
But usually JavaScript from iFrame to your web app is not allowed.

#3

Not allowed by whom? By the law? By Xojo? By Web Browsers?

#4

By law. Well, by web browser security. The techniques have been proven to be used in malicious ways in the past, so as standard security you can’t operate javascript on an iframe displaying a different domain or protocol.

#5

Thanks, Tim.

So that leaves creating URLs in my href links that directly call back into the app’s URL handler.

Anyone done that?

I mean, how does that work? I see that the framework creates links that refer to the session ID, so I guess I have to do that as well, but how do I receive those?

#6

If you’re completely in charge of the HTML being displayed I would also recommend looking into the WebSDK. You can have your links trigger Xojo events that are session aware. This should all work if the only reason you were using a HTMLViewer was to display HTML you created.

#7

If what you want to do is click on some of the links, you could simply use a HTTPSocket to get the page content.

You can then parse the content of the page, looking for ‘a href’ tags, and build a list of links.

Then no need to intervene in the page itself.

#8

Tim, I had not realized that the WebSDK was doable in pure Xojo. Thanks for pointing it out, it sounds exactly like what I need.

#9

look to [quote]Extras/WebSDK/Examples/HTMLArea.xojo_binary_project[/quote] that should implement a stub of exactly what you are trying to accomplish.

#10

You can react to a changed URL ie if they click a specific button that loads a specific page, you get an Event, and can Action that.

I use this to know if the user has paid for an item via PayPal, as I have told PayPal to jump to a specific web page (on my web site, saying Thank you) on completion of the sale.

#11