In Salerno you can find numberous places for hanging out almost every night in a week.
The hardest thing is to choose.
One of the places is Galleon. In the moment you feel like you're in a pirat empire. You can order fried stuff, which are excellent for starters and then pizza or specific type of sandwiches. Actually quite fun. Excellent for a night with friends.
You can also try fish menu during the day.
Dress Code: What ever you want, the most important thing is a good mood and smile on your face.
If you're looking for discoteque or disco-pub for live music or dancing... Salerno is the best place of Campania... (I say so 'cause I live not far from there and with my friends we prefer to go in Salerno more than in Neaples...) There are many places to meet people, listen to good music and you'd have a right choice indipendently by your age. I mean there are good restaurants, good pizza, chineese restaurant's, McDonald...
Dress Code: just be yourself...
All the restaurant, bar, pizzerie are in the center near the sea and are easy to reach from the hotels having a nice walk near the sea-side...