it is equal to how are you now a days!

Hi Amelia, they mean to ask you what is new in your life. Also if you look sad or upset they may say this to find out what is wrong with you.

what is up? (你怎麼啦﹖) It is a slang used in oral conversation. It is what's up? I don't believe that the English speker(s) will ask you what is up? Even though they mean the same as what are you up to. But, in pronounciation, they don't pronounce the same.

http://www.urbandictionary.com/define.php?term=what's+up

Hello Amelia , *It could be used as an informal inquiry, when you ask someone what is wrong: It is often contracted to "what's up?" "What's up? Why haven't you left yet?" It is almost equivalent to "怎 么 了 ？" in Chinese. * It could be used as an icebreaker as well just like "hi, how are you ?" So sometimes the one asking it doesn't expect a real answer. * It could also mean"How is it going? " ,just asking someone about their well being . So it has various connotations depending on the situation and is mostly used informally in spoken English.