The shadowOffsetY property

[No canvas support]
An example of the shadowOffsetY property

This sets the Y offset of the shadow. Values can be positive (the shadows are cast down) or negative (the shadows are cast up). Inner shadows are not supported but are achievable if you:

You can find details of inner shadows at the link below.

An example

    window.onload = function ()
        var canvas  = document.getElementById("cvs");
        var context = canvas.getContext('2d');

        var x       = 50;
        var y       = 50;
        var width   = 100;
        var height  = 100;
        context.shadowColor = '#ccc';
        context.shadowOffsetX = 0;
        context.shadowOffsetY = 30;
        context.shadowBlur = 15;
        context.fillStyle = 'red';    
        context.fillRect(x, y, width, height);