With a javascript click-event I am adding extra html-text (to be specific: an "X"-icon" within a span) to a button. I am doing this with switching the property on the span-icon-class from display: none to display: block.
The button therefore becomes bigger because of the added icon after the click event instantly.
What CSS/js do I need to add, to make this transition smooth, so that the button grows slowly bigger instead of instantly?
Thanks a lot and sorry for maybe complicated questioning.