$board is set whenever script is run.  when script has not been run before, i.e. when a visitor is new to site, I want other code to run.  but this is not happening.

<td>
                    <input type="text" name="board" <?php 
                    if(empty($board)) 
                    {
                    	printf("value=\"$board\"");
                    }
                    else
                    {
                    	printf("value=\"Enter Board Cards\" onClick=\"this.value=''\"");
                    }?>>
                </td>
          	</tr>