jQuery Background Canvas supports IE6, anti-aliases and supports opacity. But it isn't that nifty insert some corners stuff. It gives you full control about the background rendering.
Look at tis sample:
$(document).ready(function()
{
$(".Test").backgroundCanvas();
});
function DrawBackground() {
$(".Test").backgroundCanvasPaint(TestBackgroundPaintFkt);
}
// Draw the background on load and resize
$(window).load(function () { DrawBackground(); });
$(window).resize(function() { DrawBackground(); });
function TestBackgroundPaintFkt(context, width, height, elementInfo)
{
var options = {x:0, height: height, width: width,
radius:14, border: 0 };
// Draw the red border rectangle
context.fillStyle = "#FF0000";
$.canvasPaint.roundedRect(context,options);
// Draw the gradient filled inner rectangle
var backgroundGradient = context.createLinearGradient(0, 0,
0, height - 10);
backgroundGradient.addColorStop(0 ,'#AAAAFF');
backgroundGradient.addColorStop(1, '#AAFFAA');
options.border = 5;
context.fillStyle = backgroundGradient;
$.canvasPaint.roundedRect(context,options);
}
Here is the plugin, and this site makes a vast use of it:
jQuery Background Canvas Plugin