Mozilla Browser Prefix: -moz
Different from the current spec
the -moz- prefix used by Mozilla uses almost the same syntax as the unprefixed commands although some of the paramaters to those commands are different than what is used by the final W3C specification.

Mozilla recognizes only it's own prefixed commands and the unprefixed ones (as of the current writing, fall 2013):

    linear-gradient
    -moz-linear-gradient
    repeating-linear-gradient
    -moz-repeating-linear-gradient
    radial-gradient
    -moz-radial-gradient
    repeating-radial-gradient
    -moz-repeating-radial-gradient

The other differences are in the arguments to those those commands: the direction and angle. In a nutshell with a -moz- browser prefixed linear gradient command, when a direction is given in -moz- prefixed commands as words such as top or bottom, left or right then you have to invert it and prefix it with to for the unrefixed version of the command, so for example top becomes to bottom and left becomes to right.

So, directions given in words are 180 degrees out and you need to correct for that if you're converting between the two. See: ../../tests/linear/angle/#compare.

Also, when angle of rotation is given in degrees it is ninety degrees out from the spec. If you take the angle from the spec or the unrpefixed command and subtract that from 90 and use the resultant number you will have the correct angle for the -moz- prefix version of the command - even if this number is negative - which it will be sometimes - it will work just fine. See: ../../tests/linear/repeat_angle/#compare.