<!DOCTYPE html> <body> <html> <select id="test" size="8"> </select> <script> var optgroup = document.createElement("optgroup"); optgroup.setAttribute('label', 'An optgroup'); var option = document.createElement("option"); var optionText = document.createTextNode("An option"); option.appendChild(optionText); var select = document.getElementById("test"); optgroup.appendChild(option); select.appendChild(optgroup); </script> </body> </html>