JavaScript DHTML/Javascript Collections/options
"options" Example
<html>
<body>
<select id="mySelect">
<option>List Item 1</option>
<option>List Item 2</option>
<option>List Item 3</option>
<option>List Item 4</option>
<option>List Item 5</option>
<option>List Item 6</option>
</select>
<button onclick="alert(mySelect.options.length);">
Number of options in the select list
</button>
</body>
</html>