BUG: IE6 png fix and fadeIn

[jonahfox]

bug in 1.2 (and previous jqueries) when using png fixes and effects such as fadeIn()

line 881.

(parseFloat( elem.filter.match(/opacity=([^{)]*)/) )[1]) / 100).toString() : "";}

The problem is caused, because elem.filter is not null (using DXAlpha..) but does not match /opacity/ and thus we are attempting to evaluate null[1]

it can be fixed with =>

(parseFloat( (elem.filter.match(/opacity=([^{)]*)/) [0,"100"])[1]) / 100).toString() : "";}

[davidserduke]

I believe this is fixed in [4013]. Although the fix was not for this specific ticket, the result was a non-null filter that doesn't have opacity in it should now work.