Dogs are social creatures and when we come back from an absence, they want to greet us and get our attention so we can share all that love. When dogs greet they do it face to face, with our faces being so far away and high up they naturally jump up to get closer. The key to changing the jumping up behavior is to give the dogs what they want, our attention, but only when we get the behavior that we want, four feet on the floor (or a sit).
When people continue to have a problem with jumping up behavior, often it's because they misguidedly believe that they are correcting the behavior with punishment by scolding the dog, or pushing him away when he jumps up. Rather then being punitive those actions are actually reinforcing the jumping up behavior.
The way to change the behaviour is to give them what they want, our attention, but ONLY when we get what we want...a calm greeting. When your dog jumps up on you don't scold or talk to them in any way. Don't push them off or touch them in any way. Don't even look at them, as these are all forms of attention. Instead when they jump up simply walk away or turn your back, and keep doing that until they stop jumping up, and they will stop. But here is the important part...make sure you reinforce the behavior of "four on the floor' or a sit by giving them what they want - your attention. If you start to give attention and your dog once again jumps up, then you once again remove all attention and turn your back or walk away. They will eventually learn that the only way to get your attention is to remain calm and keep their feet or butts on the ground.
Dogs do what works, period. If jumping up works to get them what they want, then that is what they will do. If jumping up stops working and sitting now gets them what they want, then that is what they will do. When you stop reinforcing the jumping up behavior and consistently reinforce the calm behavior...then that is what you will get.
Some products to help stop jumping up: