Code
<!DOCTYPE html>
<html>
    <head>
        <title>html tutorial - html5 - html code - html form - In 30Sec by Microsoft Award MVP - | wikitechy onchange attribute</title>
    </head>
    <body>
        Select Wikitechy Tutorial :<br><br>
              <select name="tutorial" onchange="onChange(this.value)">
                <option value="HTML">Wikitechy HTML</option>
                <option value="CSS"> Wikitechy CSS</option>
                <option value="PHP"> Wikitechy PHP</option>
        </select>
              <script>
                 function onChange(val) {
                      alert("The Value Changed as : " + val);
            }
              </script>
    </body>
</html>

Result