( containerId , buttonSkin , forceTransparent )
containerId <HTMLElement>Container element for the Flash Player instance.
buttonSkin <String>[optional]. If defined, the uploader is rendered as a button. This parameter must provide the URL of a button skin sprite image. Acceptable types are: jpg, gif, png and swf. The sprite is divided evenly into four sections along its height (e.g., if the sprite is 200 px tall, it's divided into four sections 50px each). Each section is used as a skin for a specific state of the button: top section is "up", second section is "over", third section is "down", and fourth section is "disabled". If the parameter is not supplied, the uploader is rendered transparent, and it's the developer's responsibility to create a visible UI below it.
forceTransparent <Boolean>This parameter, if true, forces the Flash UI to be rendered with wmode set to "transparent". This behavior is useful in conjunction with non-rectangular button skins with PNG transparency. The parameter is false by default, and ignored if no buttonSkin is defined.