Answers for "select box change event in jquery"

f.select on change jquery

$('select').on('change', function() {
  alert( this.value );
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<select>
    <option value="1">One</option>
    <option value="2">Two</option>
</select>

jquery onchange input value

$("input").change(function(){
  alert("The text has been changed.");
});

dropdown option selection change event in jquery

$("select [name='element_name']").change(function(){
	// condition goes here
});

value change event jquery

$("#input").change(function(){
  alert("The text has been changed.");
});