DIAGONAL LINES

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="utf-8">
    <title> The Canvas Tag </title>
</head>

<body>

<canvas id="myCanvas" width="640" height="640" style="border:1px solid black";></canvas>

<script>

var canvas = document.getElementById("myCanvas");
var drawingTools = canvas.getContext("2d");

    drawingTools.lineWidth = 1;


for(var i = 1; i < 640; i += 10)
{
    drawingTools.beginPath();
    drawingTools.moveTo(i, 640);
    drawingTools.lineTo(640, i);
    drawingTools.moveTo(i, 0);
    drawingTools.lineTo(0, i);
    drawingTools.stroke();
}


</script>
</body>

</html>