Final answer:
Halos are usually observed around high altitude clouds like cirrostratus due to the interaction of light with ice crystals. They are not commonly found around clouds such as cumulus or stratus. 'JS Wx' likely refers to JavaScript Weather which entails handling weather data with JavaScript.
Step-by-step explanation:
Halos around clouds are typically formed when light interacts with ice crystals in high altitude clouds such as cirrostratus clouds. This effect is not commonly seen in clouds that lack these ice crystals, like cumulus or stratus clouds. When it comes to JS Wx, an abbreviation that might stand for JavaScript Weather, the key would be understanding how weather data and phenomena are represented and can be manipulated or displayed using JavaScript in a computing context.