 unique id for this widget (optional)
* @param {item(num)} an item
* @param {value=0} the minimum value if the slider is moved to total left (optional, default 0)
* @param {value=255} the maximum value if the slider is moved to total right (optional, default 255)
* @param {value=5} step between two values (optional, default 5)
* @param {text(horizontal,vertical,bottomup,semicircle)=horizontal} possible options: 'horizontal', 'vertical', 'bottomup', 'semicircle' (optional, default 'horizontal')
* @param {tex