Set value to HTML select element with jQuery

HTML

<select id="days" name="days">
    <option value="0">- Select day -</option>
    <option value="1">Sunday</option>
    <option value="2">Monday</option>
    <option value="3">Tuesday</option>
    <option value="4">Wednesday</option>
    <option value="5">Thursday</option>
    <option value="6">Friday</option>
    <option value="7">Saturday</option>
</select>

JavaScript

$(document).on('change', 'select#days', function(event)
{
    alert(event.isTrigger);
	alert('Chnage happened');
});
$(function()
{
	$("#days").trigger('change');
});