Just save it on the Form and with every click you update it from 90 to 180 and so on..then update the JS code above to reflect the value. protected   vDegrees: integer; On the button click: vDegrees := vDegrees + 90; -- you have to add some logic when it gets to 360 UniImage1.JSInterface.JSCode(#1'.el.query("img")[0].style.transform="rotate('+ vDegrees +'deg)";');