Incondition,
<!DOCTYPE HTML>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<script type='text/javascript'>
function showDay(){
alert('dkfjghdfkjg');
}
</script>
</head>
<body>
<select class="month" id="month" onChange="alert(showDay());showDay();alert('Item with index ' + this.selectedIndex + ' selected.'); alert('utyu');">
<option>Январь</option>
<option selected >Февраль</option>
<option>Март</option>
<option>Апрель</option>
</select>
</body>
</html>