JSFiddle - React, Tailwind, and code Playground

HTML

<select id="dateselect" style="width:100%;" class="form-control" >  
		                            <option value="24" >Past 24 hours</option>
		                            <option value="7" >Last 7 days</option>
		                            <option value="30">Last 30 days</option>
		                            <option value="date">Custom Date</option>
	                            </select>

JavaScript

$(function() {
    dateselect = $('#dateselect').val();
    $('#dateselect').on('change', function() {              
        dateselect = $(this).val();  
        alert(dateselect);
    });
    alert(dateselect);
});