Tryit Editor v1.8

Source Code:
<!DOCTYPE html> <html> <head> <script src="../../ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"> </script> <script> $(document).ready(function(){ $(".btn1").click(function(){ $("p").animate({borderBottomWidth:"10px"}); }); $(".btn2").click(function(){ $("p").animate({borderBottomWidth:"1px"}); }); }); </script> </head> <body> <button class="btn1">Animate</button> <button class="btn2">Reset</button> <p style="border:1px solid black">This is a paragraph.</p> </body> </html>
Result:
W3Schools.com - Try it yourself