<SCRIPT LANGUAGE="JavaScript">
            onload=function (){
            TR=document.getElementsByTagName('tr')
            for(i=0; i<TR.length; i++)
            TR[i].onclick=function (){
            var selectedValue = this.getElementsByTagName('td')[0].firstChild.nodeValue
            alert(selectedValue)
            }
            }
            document.getElementById("mnum").value = selectedValue;
            </SCRIPT>

    <script type="text/javascript">
         onload=function addRowListeners() { 
            /* source code partially from: http://bytes.com/forum/thread148858.html */
            /* Use this function as a common event listener for each row. */
            function showRowNum() {
                /* Check that the rowIndex property is
                 * supported before trying to use it.
                 */
                if('number' == typeof this.rowIndex) {
                    var rowSelected = this.rowIndex+1
                    alert('You clicked row: ' + rowSelected);
                    var table = document.getElementById('catTable');
                    alert('Table is catTable');
                    var row = table.rows[rowSelected];
                    alert('row is '+row);
                    var cell = row.cell[0];
                    alert('cell is '+cell);
                    var content = cell.firstChild.nodeValue;
                    alert('Selected content: '+content);
                    //alert();
                }
            }
            /* Check that the getElementById method is
             * supported before trying to use it.
             */
            if(document.getElementById) {
                /* Change the string, 'myTable', to reflect the actual id. */
                var table = document.getElementById('catTable'), rows;
                /* Ensure a reference was obtained and
                 * that we can access the rows.
                 */
                if(table && (rows = table.rows)) {
                    /* Add the listener to each row in the table. */
                    for(var i = 0, n = rows.length; i < n; ++i) {
                        rows[i].onclick = showRowNum;
                            
                        
                    }
                }
            }
        }
    </script>
    



<table border="1" name="catTable" id="catTable" rules="cols" width="80%" align="center" onClick="wasClicked()">
                <thead style="background-color:#cdc673">
                    <th>ID</th>
                    <th>Password</th>
                    <th>Username</th>
                </thead>
                <tbody class="scrollable">
                    <!-- Some JSP codes to populate the table //-->
                </tbody>
            </table>