Change the position of the background-image in a <div> element to center bottom:
document.getElementById("myDiv").style.backgroundPosition = "center bottom";
<!DOCTYPE html> <html> <head> <style> div {//from w w w . j av a2s . c o m background-image: url('background2.png'); background-repeat: no-repeat; width: 400px; height: 400px; border: 1px solid #000000; } </style> </head> <body> <button type="button" onclick="myFunction()">Position background image</button> <br> <div id="myDiv"> </div> <script> function myFunction() { document.getElementById("myDiv").style.backgroundPosition = "center bottom"; } </script> </body> </html>