It's typically used in a playful, lighthearted manner, similar to "hey" or "yo" in English, but with a slight connotation of surprise or excitement.
Here are some possible ways to translate "jhaan" depending on the context:
* Hey
* Look
* Listen
* Wow
* Oh, hey
* Hey there
The best translation will depend on the specific situation and the tone of the speaker. It's best to consider the overall context and the speaker's intent to find the most appropriate translation.