Now these might be spoilers. A youtuber user named Ivan Flores claims to have seen a private screening of Jurassic World's first trailer for a media focus group. Since then Universal pictures has taken down his video describing what he has seen, and I've also seen a few sites with this information claiming that the studio requested that they remove the information. From comicbookmovie.com
OPEN: UNIVERSAL and LEGENDARY logo- cut to ferryboat, filled with tourists. The camera pans around to show Isla Nublar. A few scenes pass by, showcasing the arrival to the island. The next scene shows a vehicle passing through large gates, much like the Jurassic Park gates, that read Jurassic World. Queue small montage of scenes showcasing the park, filled with tourists. (Note: at some point during these scenes title cards that read "THE PARK" "IS OPEN" appear)
One scene that is described specifically is of a vehicle casually driving through a field, surrounded by bipedal dinosaurs, likely Gallimimus. The next described scene specifically is of two passengers (likely Nick Robinson and Ty Simpkins) inside of a 'clear bubble-shaped vehicle" (the Gyrosphere), next to large Sauropods, which are likely Apatosaurs.
A few more scenes go by, which lead into a Great White Shark, hung upside-down over water, with visitors onlooking. Suddenly the water explodes, and the huge head of Mosasaur leaps upward, encompassing the shark, and pulling it under, thus soaking the guests watching in awe.
We then see a closeup of a mosquito inside of amber, and cut to Bryce Dallas Howard saying a line along the lines of "We have learned more about genetics in the past decade than the past century" and "We are now able to create our own dinosaurs from scratch".
We now see Chris Pratt for the first time, walking into a room questioning an apparent situation. We cut to see a huge wall of a paddocks interior, covered in deep scratches. It is then mentioned that the 'creature' is loose, and a line similar to "She is deadly, and she will find us" is said. Cut to a person being dragged through a dark jungle, from a first-person perspective, only showcasing his feet. Next we see someone fall into water, followed by a woman screaming in terror.
Cut to title Jurassic World, followed by Chris Pratt saying "If we're gonna do this, we do this my way" pans to a muzzled Velociraptor that he gently pats on the head. It is then followed by a scene of a pack of raptors charging through the jungle. Trailer finishes with a title card: "JUNE 12th, 2015".
Also another site has these:
-The trailer opens with tourists traveling by ferryboat to Isla Nublar, where an operational amusement park known as (what else?) “Jurassic World” is located.
-We get to glimpse some of the dinosaur-based attractions at “Jurassic World”, which include the Gyrosphere mentioned in the park map and brochure props created for the film.
-A Great White Shark is shown being fed to a large aquatic dinosaur, to the delight of onlooking park guests.
-Some dinosaur – presumably the confirmed “new dinosaur” engineered by the park’s scientists (which includes Bryce Dallas Howard’s character, who appears briefly in the trailer) – gets loose, resulting in a quick montage of the chaos that ensues.
-The trailer concludes with Chris Pratt’s character, a dinosaur handler, revealing that he has muzzled (and tamed) Velociraptors, whom he employs to help track down and recapture the renegade creature.
Currently it is being speculated that the first public trailer will be shown during Interstellar screenings next month, so we'll just have to wait and see.