qazibum,
<html>
<head>
<title></title>
<script>
var color = "";
</script>
</head>
<body>
<select onchange="color=+this.value; alert(color + ' ' + typeof color);">
<option value="15">красный</option>
<option value="25">синий</o00ption>
<option value="30">белый</option>
</select>
</body>
</html>