jQuery in own widget

Hello,
I am creating my own WP widget and am trying to use jQuery for a form validation.
For now I just want to hide the error-<p> when the page is loaded.

<table class='widget-contato'><form action=''>
		<tr><td>Nome</td><td><input name='widget_name' class='widget-contato'><p class='widget-contato-error'>Por favor, informe seu nome.</p></td></tr>
		<tr><td>Telefone</td><td><input name='widget_phone' class='widget-contato'><p class='widget-contato-error'>Por favor, informe seu nome.</p></td></tr>
		<tr><td>Email</td><td><input name='widget_mail' class='widget-contato'></td></tr>
		<tr><td>Mensagem</td><td><textarea name='widget_text' class='widget-contato'></textarea></td></tr>
		</form></table>
		<input value='Orcamento' type='submit' class='widget-contato-button'>
	</div></div>  <script>
  $(document).ready(function(){

      $(".widget-contato-error").hide();

  });
  </script>

in the header I have jQuery included. But the <p class=’widget-contato-button’> does not hide.

Can anyone help me please?

Thanks!