Sprites/Containers - Alpha Property

Also,

If you don't want to embed the font, create a rectangle graphic the same size as the textfield, set the alpha to .5 and add it as a child to the container.

var rectangle:Sprite = new Sprite()
rectangle.graphics.lineStyle(1,0x000000,0)
rectangle.graphics.beginFill(0xFFFFFF,0.5)
rectangle.graphics.drawRect(0,0,1000,100)
rectangle.graphics.endFill();

container.addChild(myText);
container.addChild(rectangle)

You'll need to embed the font and include the font in your library to make it work. On your library panel, click the little down arrow with 3 lines beside it (on the top right) and select New Font. Select your font and add it to the Library, and then make sure to check "Export for Actionscript" on the linkage. After that, make sure to set myText.embedfonts = true.

Hope that helps!

Cheers,
FlashTastic

In Actionscript 3.0, alpha is a percentage, not an integer. The value will always be between 0 and 1. You'll need to change it to container.alpha = 0.5;

Cheers,
FlashTastic