[jquery] How to get all child inputs of a div element (jQuery)

You need

var i = $("#panel input"); 

or, depending on what exactly you want (see below)

var i = $("#panel :input"); 

the > will restrict to children, you want all descendants.

EDIT: As Nick pointed out, there's a subtle difference between $("#panel input") and $("#panel :input).

The first one will only retrieve elements of type input, that is <input type="...">, but not <textarea>, <button> and <select> elements. Thanks Nick, didn't know this myself and corrected my post accordingly. Left both options, because I guess the OP wasn't aware of that either and -technically- asked for inputs... :-)