<html> <head> <script type="text/javascript"> function marcar(obj) { chk = obj.parentNode.parentNode; chk = chk.getElementsByTagName('input')[1]; chk.checked = (obj.value.length > 0); chk.disabled = !chk.checked; } </script> </head> <body> <table> <tr> <td>negro</td> <td><input type="text" onKeyUp="marcar(this)" /></td> <td><input type="checkbox" disabled="disabled" /></td> <tr> <tr> <td>azul</td> <td><input type="text" onKeyUp="marcar(this)" /></td> <td><input type="checkbox" disabled="disabled" /></td> <tr> </table> </body> </html>