I have seen in the comments of Is quoting the value of url() really necessary? and CSS background-image - What is the correct usage? that Mac IE 5 does not support quotation marks inside the url() function.
Also PPK's CSS page does not mention the url() function at all: http://www.quirksmode.org/css/contents.html
So I would like to know what browser support is like for this function. What browsers recognise the value, which ones require what quotation marks, whitespace, and so on.
I realise that everything released in the past five years probably support all syntaxes. It's the older browsers I am thinking of.