A ver, genero un código en php para un evento en javascript y me da error de validación del w3c.
Os pongo el código :
Código HTML:
<td><input type="button" name="grabar_form_ficha_clonar" value="Clonar" onclick="location = 'ficha_articulos.php?id=<?php echo $tupla[0]; ?>&cl=si'" /></td>
Cannot generate system identifier for general entity.
An invalid character reference was found in the "onclick" attribute value. Often this is because the ampersand character was not properly encoded as the entity "&". Other causes of invalid references are misspelled entity names and missing semicolons.
Saludos.
(para mí). Yo probé el & y me había dejado el ";". 
