First game stuck already

Hi all starting my first game but already stuck on the canvas.

trying to get this to show in my chrome browser i can see the black border but cant seem to see the green fill.

Is this the best way, i am using notepad++ then running it in my browser to test.

code


<!DOCTYPE html>
<html>
<head>
<title>Shape Warz</title>
</head>

<body>
<canvas id="myCanvas" width = "300" height = "300" style = "border: 1px solid black">Not Supported</canvas>
<script>

var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.fillStyle = "green";
ctx.fillRect(0,0,150,75):

</script>
</body>

</html>

Ok now finally i keep progressing but when i run the code i have been checking using consol in chrome is this a good way to go about it or should i download a better program???