Can’t seem to find anything online about this: how do you achieve zoom of a map in a browser (but not browser zoom) using a touchscreen in Windows 10?

This particular problem presents itself with jinjianginns.com, when one tries to perform a map search (grey button on main site). The map view has no + or – to zoom out or in with, and the intuitive thing to do on a PC is to zoom with the scroll wheel on the mouse.

You can blame it on the UI. But I think this is another instance of Windows 10’s immature touch capabilities. Can’t get it to work even with Microsoft Edge.