Transparency Context.fill Style In Canvas Html5

I write this javascript code : context.shadowOffsetX = 5; context.shadowOffsetY = 5; context.shadowBlur = 4; context.shadowColor = 'rgba(255, 0, 0, 0.5)'; context.fillStyle = '#f00

Solution 1:

Try making the fillStyle RGBA, too.

context.fillStyle = 'rgba(255, 0, 0, 0.5)';
context.fillRect(x, y, w, h);