How would I submit a game that goes on forever (i.e. Chrome Dinosaur Game). I have a few ideas, like getting a certain score but i'm not sure.

you can't submit those kinds of games to the site

besides, how would you speedrun it? you can track highscores on other websites

main problem with speedruns of chrome dinosaur is "reaching certain score" would tie for everyone

Yeah autoscroller with no end condition is pretty much as far removed from speedrunning as it gets. Consider submitting to a high score site instead, like CyberScore, or TwinGalaxies (looks like it actually is on TwinGalaxies already), or whatever is considered good for that nowadays.