Question

My code works on Chrome but not on Firefox… in Firefox… whenever this piece of code launches..

canvas.addEventListener('keydown');

I get this error:

Not enough arguments
[Break On This Error]   

canvas.addEventListener('keydown');

I have var canvas near the top as well as this:

canvas = document.getElementById("canvas");
    canvas.width = 512;
    canvas.height = 352;
context = canvas.getContext("2d");

I do not know why it works fine on Chrome but not Firefox…

Answer 1

You need a function that executes when the event fires. It can be specified either inline like this:

canvas.addEventListener('keydown', function(e) {
    // your code here to handle the event
});

or it can be specified like this:

function keyHandler(e) {
    // your code here to handle the event
}

canvas.addEventListener('keydown', keyHandler);

Without an event handler function, there is nothing for the event handler to do as no code would execute when the event fires.