<select id="mySelect">
    <option value="1">Yes</option>
    <option value="2">No</option>
</select>
<input type="button" id="demo" value = "Demo" />
<script type="text/javascript">
    $("#demo").live("click", function () {
        //Get Index of the option with value = 1
        var optionIndex = $("#mySelect option[value=1]").index();
        alert(optionIndex);
    });
</script>