jQuery Selector :animated
$(":animated")
The :animated selector selects all elements that are currently animated.
<!DOCTYPE html> <html> <head> <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script> <script> $(document).ready(function(){ function aniDiv(){/*from w w w. j ava 2 s .c o m*/ $("div:eq(0)").animate({width: "50%"}, "slow"); $("div:eq(0)").animate({width: "100%"}, "slow", aniDiv); } aniDiv(); $(".btn1").click(function(){ $(":animated").css("background-color", "red"); }); }); </script> </head> <body> <button class="btn1">Change color of the animated element</button> <div style="background:blue;">Div 1</div> <div style="background:green;">Div 2</div> <div style="background:yellow;">Div 3</div> </body> </html>