JAVASCRIPT

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; // 2
	var strUser = e.options[e.selectedIndex].text; //test2
</script>

js get selected option element

var yourSelect = document.getElementById( "your-select-id" );
alert( yourSelect.options[ yourSelect.selectedIndex ].value )

get selection value javascript

var e = document.getElementById("ddlViewBy");
var strUser = e.value;

get selected option from select javascript

const selectedValue = document.getElementById("color-id").value;