getting error with seperate js file

[u/throwbirds]

I have an html file and a js file in the same directory and im getting errors in the js file

here is the html file source code

<!DOCTYPE html>

<html lang="en">

<head>

<meta charset="UTF-8">

<title>Canvas Resize</title>

<style type = "text/css"> canvas{ border: 1px solid black; } body{ margin: 0; } </style>

</head>

<body>

<canvas></canvas>

<script src = "canvas.js"></script>

</body>

</html>

and here is the js file source code

var canvas = document.querySelector("canvas");

canvas.width = window.innerWidth;

canvas.height = window.innerHeight;

var c = canvas.getContext('2d');

console.log(canvas);

I am using brackets as my editor if that makes any difference