console.log(111);
console.log($("form~input").attr("name"));
console.log(222);
console.log($("form input").attr("name"));
console.log(333);
console.log($("form>input").attr("name"));
<form>
<label>Name:</label>
<input name="name" />
<fieldset>
<label>Newsletter:</label>
<input name="newsletter" />
</fieldset>
</form>
<input name="none1" />
<input name="none2" />