Change the backgroud colour

Im using crop fullscreen mode to support multiple mobile screen sizes. The background is white. How do I change it to another colour?

Do you mean on your web page or in the game itself? In the game, go to the layer's panel and click on the default layer in the game. This layer is set up with a solid background, while all other layers are set up by default with transparent backgrounds.

Once you have that default layer selected, go the the Properties panel and you'll see a field for background color that you can change.

If you mean the "envelope" or "bars" around your game that appear because of scaling, they should automatically be black. If they are not, I'd report it as a bug. (In appmobi right now I'm encountering a white bar on the rhs that is due to some sort of scaling problem, but I assum you aren't using appmobi.)

If you mean on the web page, that is just like you'd change any web page.

In crop mode, the game can be played in an area bigger than the layout. I have all my lahouts set to the target mobile window size so I can see what I am doing and set anchors, then I put a 1024 background image on them.

However, if the player should have a large screen, and open the game window bigger than 1024 (in crop mode), there is a white background around it. This is what I need to change. I could of course create a background image which is larger than the largest monitor available and put it on every laout, but apple keep bringing out even higher res ones. Putting a 4k x 4k black backgroud image on each layout for mobiles is getting a bit extreme.

Im hoping the white background outside of the layout is changable somehow (even If I have to write a javascript parser to change some code in the compiled js).