'index' Example
<html> <body> <select id="mySelect" size=5> <option id="o1">1</option> <option id="o2">2</option> <option id="o3">3</option> <option id="o4">4</option> <option id="o5">5</option> </select> <input type="button" value="1" onClick="function1(o1);"> <input type="button" value="2" onClick="function1(o2);"> <input type="button" value="3" onClick="function1(o3);"> <input type="button" value="4" onClick="function1(o4);"> <input type="button" value="5" onClick="function1(o5);"> <script language="JavaScript"> function function1(elem) { alert("Index: "+ elem.index); } </script> </body> </html>