jQuery addClass example
Change class name on click in jQuery
HTML
<form>
Deseja anonimato?
<input type="checkbox" id="anonimo">
<div id="containerInput">
<input type="text" id="nome" placeholder="seu nome">
<input type="text" id="email" placeholder="seu email">
<input type="text" id="telefone" placeholder="seu telefone">
</div>
</form>
JavaScript
$('#anonimo').click(function () {
var texto = this.checked ? 'anonimo' : '';
$('div[id="containerInput"]').find('input:text').each(function (i, obj) {
$(obj).val(texto);
});
});