Desktop: how to display a window when the mouse is over an html tag?

I created a method to export a Lst stored in a ListBox with success.

Now, I want to be able to add a special feature (javascript) that display an image and some text comment when the Mouse Cursor is above certain TABLE Cell.

I only found Alert(), but that window needs a click in and this is not what I want.

I searched @ w3schools.com but I do not found.

I precisely remember where I saw this feature, but totally forgot the URL (strange, isn’t it ?) or worst, the web site disappears.

In JavaScript you can add mouseover event handler for all objects. Then when mouse is over something, you can calculate position relative to website. You may adjust for scroll position of the webpage and thus get the position relative to HTMLViewer.
Pass that back to Xojo via JavaScript.
Next you can add window position in Xojo code and get on screen position.
Finally create floating window and place it there to show context help.

Thank you Christian for your kind answer.

Unfortunately, this is “pure” html created by a Xojo Desktop applicatio, but it is run locally on a browser: once the html file is created, Xojo is unknow to it.

That is why I talked about

Alert(“Hi Christian”)

https://www.w3schools.com/jsref/met_win_alert.asp

Christian gave you a full implementation outline, and I would recommend the same process. It can be implemented since you say you’re in control of the HTML.

I have never seen Javascript alert() work in a Xojo HTMLViewer, but I haven’t gone HTMLViewer hacking in a while.

Are-you kidding ?

This is totally impossible to do. As I wrote earlier, once my Xojo built html file have been created, Xojo is no move involved in the operation (the html is passed to Firefox), so there cannot be any Xojo window.

Are you looking for “onmouseover” instead of “onclick”?

Feel free to do it all in JavaScript.
e.g. show a div with position set to the one of the mouse cursor.
You may find documentation on how to code tooltips in JavaScript on the web.