JMP uses the Internet Explorer ActiveX control in browsers contained within JMP windows. These include the File > Internet Open… and the Web browser display box browsers.
The IE control defaults to using Internet Exploerer version 7 compatibility settings which does not handle many newer HTML/CSS features. This can result in popups such as you're seeing here. If you control the HTML, you can set the document compatibility mode using a <meta> tag (see below for links).
Usually you do not control the HTML source so for those cases, there is another fix. There is a registry key you can set to instruct the IE control to use a newer rendering engine such as IE 9,10, or 11. As of JMP 13, the JMP setup program will set the registry key for IE 11 compatibility mode.
It’s worth noting this registry key will affect all instances of jmp.exe launched no matter the JMP version.
To make the change, open the Windows registry editor by running regedit.exe then navigate in the tree to this location:
HKEY_CURRENT_USER SOFTWARE Microsoft Internet Explorer Main FeatureControl FEATURE_BROWSER_EMULATION
Once there, you can right-click and add a new DWORD (32-bit) value.
Here's the value to use IE 11 capabilities.
Value name: jmp.exe Value data: 11000 (Set the 'Base' to Decimal)
Once set, relaunch JMP and try again.
For reference, the steps above are based on information from this page.
It's also possible to update web pages to indicate that they should be rendered with the more modern rendering engine but you may not always have full control over the HTML being used. These pages describe tags which can be used to control the rendering mode a particular page uses. This may be important for older intranet pages which were written with a particular version in mind.