Consider:
File script.js,
    function AdaugaComboBox(id, name){
        var select_tag = document.getElementById(id);
        select_tag.innerHTML += "<select name='"+name+"'><option value='0'>Selecteaza autor</option></select><br/>";
        return true;
    }
and file index.html:
<html>
    <head>
        <script src="js/script.js" type="text/javascript"></script>
    </head>
    <body>
        <table>
        <tr>
            <td id="autori">...</td>
        </tr>
        <tr>
            <td>
                <input type="button"
                       value="Adauga autor"
                       onclick="AdaugaComboBox('autori', 'autori[]')"/>
            </td>
        </tr>
        </table>
    </body>
</html>
The scope of the function is to add a combo box to the specific TD in the TABLE. But when I press the button this error appears:
AdaugaComboBox is not defined
Why?
Update:
!!! I've fixed it. The problem was with another function.