====== setAlpha ======

  * Parameters & Types:
     * playerid: number player ID
     * uiid: string the UIID of the custom UI
    * elementid: the UIID of the string element
    * alpha: number transparency
  * Return value and type:
    * ErrorCode. OK
  * The main purpose of this method is to set the transparency of the component
  * Specific use cases are as follows:
<code>
--This function is executed when the player clicks on the block
local function clickblock(event)
    local playerid=event.eventobjid--Click on the player's mini number of the block
    local uiid="6997615793455979871"--Interface ID
	local elementid="6997615793455979871_1"--Component ID
	local alpha=99--transparency
    --Set component transparency
    Customui:setAlpha(playerid, uiid, elementid, alpha)
end
ScriptSupportEvent:registerEvent([=[Player.ClickBlock]=], clickblock)
</code>