choice.value; js code example
Example 1: javascript get selected option
var e = document.getElementById("selectElementID");
var value=e.selectElement.options[e.selectedIndex].value;// get selected option value
var text=e.options[e.selectedIndex].text;//get the selected option text
Example 2: html get selected option javascript
<select id="ddlViewBy">
<option value="1">test1</option>
<option value="2" selected="selected">test2</option>
<option value="3">test3</option>
</select>
<script>
var e = document.getElementById("ddlViewBy");
var strUser = e.value;
var strUser = e.options[e.selectedIndex].text;
</script>