Dropdown and radio help

Ok so I was messing with this site..And I am having problems with the dropdown and radio buttons

Code:

              <td valign="center"><strong>* Birth Date </strong></td>
             <td><strong>
               <select name="requiredbirthmonth" id="requiredbirthmonth">

                 <option selected="selected">mm</option>

                  <option>1</option>

                  <option>2</option>

                  <option>3</option>

                  <option>4</option>

                  <option>5</option>

                  <option>6</option>

                  <option>7</option>

                  <option>8</option>

                  <option>9</option>

                  <option>10</option>

                  <option>11</option>

                  <option>12</option>
                </select>

                -
                <select name="requiredbirthday" id="requiredbirthday">
                  <option selected="selected">dd</option>

                  <option>1</option>

                  <option>2</option>

                  <option>3</option>

                  <option>4</option>

                  <option>5</option>

                  <option>6</option>

                  <option>7</option>

                  <option>8</option>

                  <option>9</option>

                  <option>10</option>

                  <option>11</option>

                  <option>12</option>

                  <option>13</option>

                  <option>14</option>

                  <option>15</option>

                  <option>16</option>

                  <option>17</option>

                  <option>18</option>

                  <option>19</option>

                  <option>20</option>

                  <option>21</option>

                  <option>22</option>

                  <option>23</option>

                  <option>24</option>

                  <option>25</option>

                  <option>26</option>

                  <option>27</option>

                  <option>28</option>

                  <option>29</option>

                  <option>30</option>

                  <option>31</option>
                </select>
                -
                <select name="requiredbirthyear" id="requiredbirthyear">
                  <option selected="selected">yyyy</option>

                  <option>1994</option>

                  <option>1993</option>

                  <option>1992</option>

                  <option>1991</option>

                  <option>1990</option>

                  <option>1989</option>

                  <option>1988</option>

                  <option>1987</option>

                  <option>1986</option>

                  <option>1985</option>

                  <option>1984</option>

                  <option>1983</option>

                  <option>1982</option>

                  <option>1981</option>

                  <option>1980</option>

                  <option>1979</option>

                  <option>1978</option>

                  <option>1977</option>

                  <option>1976</option>

                  <option>1975</option>

                  <option>1974</option>

                  <option>1973</option>

                  <option>1972</option>

                  <option>1971</option>

                  <option>1970</option>

                  <option>1969</option>

                  <option>1968</option>

                  <option>1967</option>

                  <option>1966</option>

                  <option>1965</option>

                  <option>1964</option>

                  <option>1963</option>

                  <option>1962</option>

                  <option>1961</option>

                  <option>1960</option>

                  <option>1959</option>

                  <option>1958</option>

                  <option>1957</option>

                  <option>1956</option>

                  <option>1955</option>

                  <option>1954</option>

                  <option>1953</option>

                  <option>1952</option>

                  <option>1951</option>

                  <option>1950</option>

                  <option>1949</option>

                  <option>1948</option>

                  <option>1947</option>

                  <option>1946</option>

                  <option>1945</option>

                  <option>1944</option>

                  <option>1943</option>

                  <option>1942</option>

                  <option>1941</option>

                  <option>1940</option>

                  <option>1939</option>

                  <option>1938</option>

                  <option>1937</option>

                  <option>1936</option>

                  <option>1935</option>

                  <option>1934</option>

                  <option>1933</option>

                  <option>1932</option>

                  <option>1931</option>

                  <option>1930</option>

                  <option>1929</option>

                  <option>1928</option>

                  <option>1927</option>

                  <option>1926</option>

                  <option>1925</option>

                  <option>1924</option>

                  <option>1923</option>

                  <option>1922</option>

                  <option>1921</option>

                  <option>1920</option>

                  <option>1919</option>

                  <option>1918</option>

                  <option>1917</option>

                  <option>1916</option>

                  <option>1915</option>

                  <option>1914</option>

                  <option>1913</option>

                  <option>1912</option>

                  <option>1911</option>

                  <option>1910</option>

                  <option>1909</option>

                  <option>1908</option>

                  <option>1907</option>

                  <option>1906</option>

                  <option>1905</option>

                  <option>1904</option>

                  <option>1903</option>

                  <option>1902</option>

                  <option>1901</option>

                  <option>1900</option>
              </select></strong></td>

          </tr>

          <tr>
            <td>&nbsp;</td>
            <td><strong>* Gender</strong></td>
            <td><input name="requiredgender" value="male" type="radio"> Male
            <input name="requiredgender" value="female" type="radio"> Female</td>
          </tr>

          <tr>
            <td>&nbsp;</td>
            <td><strong>* Marital Status</strong> </td>
            <td><select id="14" name="requiredmarried" required="true">
                <option value="" selected="selected">Please make a selection</option>
                <option id="1" value="n">Single</option>
                <option id="2" value="y">Married/Committed</option>

            </select>            </td>
          </tr>
        </tbody>
      </table>
      &nbsp;&nbsp;
    </td>
  </tr>
  <tr valign="top">

    <td align="left" valign="top" width="725"></td>
  </tr>
  <tr class="tablealltext">
    <td align="left" valign="middle"><input name="optin3" class="clsRadio" onclick="" value="y" checked="checked" type="checkbox">
      I
    would like to receive  special offers from Vázquez &amp; Rincón</td>

This is what I am using for the javascript and it doesnt work. Can someone tell me why? I want to learn so no spoonfeeding please.

Code:

JS8 := "javascript:document.getElementById('requiredbirthmonth').value='" userinput8 "';void(0)"

JS9 := "javascript:document.getElementById('requiredbirthday').value='" userinput9 "';void(0)"

JS10 := "javascript:document.getElementById('requiredbirthyear').value='" userinput10 "';void(0)"

JS11 := "javascript:document.getElementById('requiredgender').click (male);"

JS12 := "javascript:document.getElementById('requiredmarried').click (Single);"