CSS 2.1 Support of comma as separator in clip: rect(valOffsetTop, valOffsetRight, valOffsetBottom, valOffsetLeft)

Reference: "Authors should separate offset values with commas. User agents must support separation with commas (...)."
CSS 2.1, Section 11.1.2 Clipping: the 'clip' property, shape value

"Internet Explorer takes their usual route and ignores the required comma separated values and only supports the optional comma-less method. So, even though using commas is the correct method, you'll need to drop the commas in order for the clip property to work in Internet Explorer (even in IE7)." Misunderstood CSS Clip by Nicholas Gagne.

This is also reported in the tutorial Creating Thumbnails Using the CSS Clip Property by seifi.org in the following manner:
"The W3C recommendation suggests using commas between the coordinates, however this is broken in Internet Explorer. Strangely using the commas in IE does not work when in standards-compliant mode, but it does work when in quirks mode."

Firefox 1.5.0.7, Firefox 2.0, Opera 9.02, Konqueror 3.5.4, Safari 2.0, Safari 3.0.2, NS 6.2, NS 7.0, NS 7.1, NS 7.2 and MSIE 5.5 all pass this test.