问HTML5帆布铬碎44.0.2403.125米

EN

var canvas = document.getElementById("drawing");
        //  if the canvas element exists 
        if (canvas != null) {
            var ctx = canvas.getContext("2d");
            ctx.setLineDash([null]);
            ctx.lineWidth = 0.5;
            ctx.strokeStyle = "#eeeeee";

            // horizontal grid lines
            for (var i = 0; i <= canvas.height; i = i + 10) {
                ctx.beginPath();
                ctx.moveTo(0, i);
                ctx.lineTo(canvas.width, i);
                if (i % parseInt(50) == 0) {
                    ctx.lineWidth = 2;
                } else {
                    ctx.lineWidth = 0.5;
                }
                ctx.closePath();
                ctx.stroke();
            }

            // vertical grid lines
            for (var j = 0; j <= canvas.width; j = j + 10) {
                ctx.beginPath();
                ctx.moveTo(j, 0);
                ctx.lineTo(j, canvas.height);
                if (j % parseInt(50) == 0) {
                    ctx.lineWidth = 2;
                } else {
                    ctx.lineWidth = 0.5;
                }
                ctx.closePath();
                ctx.stroke();
            }

        }

    }