In precisely the same way as. For example, He's signing his name just as he's always done it. [Early 1600s]
Also, just so. To the same degree as. For example, Jim's running just as fast as his friend, or He intended to give them just so much work as they could do in a day. [Late 1600s] Also see just so.
Examples from the Web for just as
Then just as startling, just-as unprovable as the flash of a shooting star, her glance flashed up at Barton.Little Eve Edgarton|Eleanor Hallowell Abbott