write a javascript program to create option list of images and then display images in new window as per selection

<script type="text/javascript">

function dropdownlist(listindex)
{
switch (listindex)
{
case "1" :
window.open("http://www.c-sharpcorner.com/","_blank","toolbar=yes, location=yes, directories=no, status=no, menubar=yes, scrollbars=yes, resizable=no, copyhistory=yes, width=400, height=400")
break;
case "2" :
window.open("http://www.c-sharpcorner.com/Code/2008/Feb/Expand-Collapse-Div-on-CheckBox-Click.aspx", "_blank","toolbar=yes, location=yes, directories=no, status=no, menubar=yes, scrollbars=yes, resizable=no, copyhistory=yes, width=400, height=400")
break;
case "3" :
window.open("http://www.c-sharpcorner.com/forums/thread/194881/this-will-be-your-first-game-with-