Why code pauses when alert is exceuted ?

Question

Why the css stops when alert is given????

Answer 1

🎃#H P 22™🎃
If we add key frames in css and add a alert somewhere in the js .....
When the alert comes the keyframes do not animate till we press ok

Answer 2

Andy(Anand)
It's not like animation don't run behind alert box , the animation works there but as alert box come it takes all focus and the animating screen freez and seem as animation stoped but when you will clear alert you will find animation start from different position with respect to that where it was freez.

The concept is alert box /modals act as window which freez other window when come into existance.