var canvas = document.getElementById('canvas');

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

//往文字上描边

ctx.lineWidth = 2;

ctx.font = "bold 100px serif";

ctx.fillStyle = 'red';

ctx.fillText("Hello world", 50, 200);

ctx.font = "bold 100px serif";

ctx.strokeStyle = 'blue';

ctx.strokeText("Hello world", 50, 200);

//往文字外描边

ctx.lineWidth = 2;

ctx.font = "bold 100px serif";

ctx.strokeStyle = 'blue';

ctx.strokeText("Hello world", 50, 400);

ctx.font = "bold 100px serif";

ctx.fillStyle = 'red';

ctx.fillText("Hello world", 50, 400);

样式：