In Safari, why are windows opened via Javascript 2 pixels wider and 1 pixel higher than requested?

In Safari, why are windows opened via Javascript 2 pixels wider and 1 pixel higher than requested?

(And in Firefox, why are these windows 3 pixels shorter than requested!?) The extra pixels are within the content area of the window.

Test 1

When I attempt to open a 400×200 pixel window in Safari, why is it 402×201 pixels?

function test_1 ()
{
	newWindow = window.open ('ruler.html', 'Ruler', 'width=400,height=200,scrollbars=no');
}

Test 2

When I attempt to open a 200×300 pixel window in Safari, why is it 202×301 pixels?

function test_2 ()
{
	newWindow = window.open ('ruler.html', 'Ruler', 'width=200,height=300,scrollbars=no');
}

If anyone knows a sane way of fixing this, or an explaination of why this is happening, drop me a mail, or leave feedback on my weblog.