Salam, Well. Not all are haram. It depends on the country you live. if you live in a Muslim country, the gelatine used would be halal. But if you live in non-Muslim countries then go for halal brands.
It depends really, as has been said, if it contains gelatine, then the gelatine has to be halal otherwise it is haraam (just look for the halal label).
Here in England, I tend to go for the vegetarian gummy sweets (no gelatine) - I actually prefer them to gelatine ones, they're softer to chew.
But go easy on them anyway They're 'empty-calories', just sugar!