javascript – Problems with the function with the game Space Invaders

I'm new to designing games and I have to create a game for my project, but I still find an error related to:
index.html: 93 Uncerded TypeError: Property can not be read & # 39; innerHTML & # 39; from undefined
in drawMissiles (index.html: 93)
in gameLoop (index.html: 140)

Any ideas to solve this problem? I need help as soon as possible, as my project will be delivered soon. Thank you.

                draw missiles ()

}

function drawMissiles () {
document.getElementsByTagName (& # 39; missile & # 39;)[0].innerHTML <— (index.html: 93)
for (var i = 0; i <missiles.length; i ++) {
document.getElementById (& # 39; missile & # 39;). innerHTML + =

;