Jot down a Firefox backgroundpostion-x and-y problem

Today to help Master wrote a day project, and later in the test of a display ascending and descending label above, I used a backgroundposition-y to determine the current icon state, but can not be used to use closures or a clock means, under Firefox is always not normal display. Tangled up a long time later finally found. The original Firefox people do not support to write this separately

It only supports this notation.

Obj.style.backgroundposition:x y;

Embarrassed Ah ... I thought I thought it was my own hole.

Continue writing the project tomorrow. By the way, look at the book just arrived.

Jot down a Firefox backgroundpostion-x and-y problem