How do i check if any point inside a rectangle lies on a triangle

yea, as i said on the title i want to make a platformer game with spikes and walls, i already did walls but i cant do a hitTest with triangular spikes anybody know how to do them?

for(var i = 0; i <= 100; i++){
            if(//what should i put here){
                document.write('game over');
            }
        }//Spikes