<!DOCTYPE html> <html> <body> <select id="a"> <option>Option 1</option> <option>Option 2</option> <option>Option 3</option> <option>Option 4</option> </select> <script> document.body.offsetWidth; var x=document.getElementById('a').options; x[1].defaultSelected = true; x[2].defaultSelected = true; x[3].defaultSelected = true; </script> </body> </html>