1999 Toyota 4 runner.Someone hooked the the leads from jumper box to battery wrong and now it won't crank

Start checking fuses, power distribution box first. Hope it was only a main fuse but you won't know until you get it running.

I agree with tennisshoes. Check the fuses first, but there may be more damage further up the line. I've seen this happen before, and take-out electronic modules (engine computer, alternator ...etc). Keep the negative terminal off of the battery, when you replace a blown fuse(s) (If you find any blown). While you try to re-connect the negative terminal, after fuse replacement, lightly place the cable/clamp back on (wearing a dry cloth glove on your hand, would be a good idea. Rubber gloves, melt to skin). This is a precaution for burned/shorted wiring, damaged modules, shorted alternator, etc... If there is a large spark/arc, smoke anywhere, smell burning plastic/electrical, when reconnecting the the battery, stop dead in your tracks, leave the terminal off, and have a mechanic look into the problem. If there is no issue, get a friend to be ready to disconnect the battery. If there is an issue, when you try to start the car, you friend can pull that terminal off quickly . An "ABC" rated fire extinguisher, on hand, would not be a bad idea. All of this might sound like overkill, but I don't know what your automotive skill level is. A fire extinguisher for your home/garage, is not overkill. Most localities require shops to have extinguishers, and having one at home, might save your life one day. And finally,... you did all of that, and no smoke/fire/nor car start. Get it to a shop, there is more damage than you probably can diagnose by yourself.