<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; // 2
var strUser = e.options[e.selectedIndex].text; //test2
</script>
var yourSelect = document.getElementById( "your-select-id" );
alert( yourSelect.options[ yourSelect.selectedIndex ].value )
const selectedValue = document.getElementById("color-id").value;