if you mess up the keys at the start as i have its not possible to change them

cant change them even after clearing browser either ... unplayable

You should still be able to use the arrow keys and space bar to navigate the menus. (Controls can be remapped in the options menu.) You can also delete the config for the game and it will ask you to set new keys. (I'm not actually sure where the config file for an HTML game is kept though.)

What keys did you set?