About CSS multi-class selectors under IE6

The notation for multi-class selectors. For example:

#my. c1.c2 {color:red;}
. c1.c2 {color:red;}

These are supported by browsers such as Ie7+/ff/opera/safari.

In IE6, however, the latter class name overrides the previous class name, that is, the above example is IE6 understood as:

#my. c2 {color:red;}
. c2 {color:red;}

Similarly:

#my. c1.c2.c3 {color:red;}
IE6 understood as #my. c3 {color:red;}
. c1.c2.c3 {color:red;}
IE6 understood as. c3 {color:red;}

So when developing a CSS effect with multiple classes, pay attention to the IE6 problem. The best way to do this is not to use the form of a class combination.