<!DOCTYPE HTML>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
</head>
<body>
<select name="select_delivery" onchange="alert(this.value)">
<option selected="" cost="350" value="moscow">Для Москвы и Московской области</option>
<option cost="0" value="moscow2">Для Москвы и Московской области(бесплатная)</option>
</select>
<script>
var sel = document.getElementsByName('select_delivery')[0];
window.setTimeout(function ()
{
sel.value = "moscow2";
sel.onchange()
},2000)
</script>
</body>
</html>