Seamonkey version 2.49.4 does not run FirstGlance in Jmol.

SeaMonkey support for Java has been removed in version 2.53.1.

SeaMonkey (available for Windows and OS X) is a Mozilla-based browser that supports Java, at least up to version 2.49.4 current in January, 2019 through July, 2020. All recent macOS operating systems are 64 bit. It is harmless to download it and try it - if you have a 32 bit operating system, it won't run.

Waterfox Classic is available only for 64-bit operating systems.

Waterfox Classic (available for Windows and OS X) is very similar to Firefox and supports Java (as of July, 2020, our most recent test). Pale Moon ( Windows only) is an independent browser, very similar to Firefox, whose developer has announced indefinite support for NPAPI plugins (including Java), and hence is an alternative to continue running Jmol applets inside web pages, at least while Oracle continues to provide the Java Plug-in. Safari versions through 11 support Java (through OS 10.11 El Capitan), but Safari 12 and later do not support Java (OS 10.12 Sierra and later). See below for details for each of these browsers. Internet Explorer supports Java as of November, 2017. The HTML5 implementation of Jmol, JSmol, works in Opera. The HTML5 implementation of Jmol, JSmol, works in Edge, although rotation is jerkier and operation is slower than in Firefox or Chrome.

However, Internet Explorer 11 is available in Windows 10 for use with Java.

The Microsoft Edge browser (new in Windows 10) does not support Java. The HTML5 implementation of Jmol, JSmol, works just fine in Firefox. Until sometime in 2018, there was a special version of Firefox called Extended Support Release (ESR) that supported Java however, later ESR versions no longer support Java. That change happened in March 2017 and had been announced well in advance. The Mozilla Firefox browser does not support Java (including the Java-dependent version of Jmol) since version 52 of the 32-bit browser the 64-bit Firefox has never supported Java. The HTML5 implementation of Jmol, JSmol, works just fine in Chrome. This change happened in late 2015 and had been announced well in advance. The Google Chrome browser does not support Java (including the Java-dependent version of Jmol). Official browser compatibility documentation for Java. Java Applets do not work in Chrome, Firefox, Edge, or Opera 7.1.1.2 Internet Explorer: Enabling Java.7.1.1.1 Accessing Internet Explorer in Windows 10.1 Java Applets do not work in Chrome, Firefox, Edge, or Opera.

Java plugin for safari