为什么在谷歌和火狐里都只有个边框？代码明明和老师的一样啊，工具用的sublime3
<!DOCTYPE html>
<meta charset="utf-8">
<html>
<head>
<title>canvas</title>
<script>
window.onload=function(){
var canvas = document.getElementById("canvas");
canvas.width = 1024;
canvas.height = 768;
var ctx = convas.getContext("2d");
ctx.moveTo(100,100);
ctx.lineTo(700,700);
ctx.stroke();
}
</script>
</head>
<body>
<canvas id="canvas" style="border:2px solid red;"></canvas>
</body>
</html>
