My html canvas has a whitish background around its edges hw do i remove it.

The canvas is rectangular. What your screenshot shows is not a rectangular whitish outline. This means the problem is your assets, not the canvas. The white outlines you have on your assets are because they were composed with antialiased edges against a white background. There are two ways to fix this. First, you can compose your assets without antialiased edges so they don't get color fringing. Second, you can save you assets as PNGs with an alpha channel (transparent background). This will allow your assets' edges to composite smoothly with whatever's behind them, at the cost of a slightly larger file size.