JQuery basics - Selecting elements inside a cached element

Sorry but this is a really basic jQuery syntax question, but I can't find anyone discussing it anywhere (probably as I don't know the correct terms to search for).

I want to select/cache a using a variable and then later get the value of checked inputs within that . Now I know I could do this without caching as:

var questionID = (a string)
$(questionID + " input:radio:checked").val()

But I use the div#'questionID' object a number of times so want to cache it i.e.

questionID = '#' + ...Something that changes ...
$question = $(questionID);

Now that $question is a jQuery object I can't work out how to select things inside it (without using children())

For example the following don't work:

$question.(' input:radio:checked)
$($question 'input:radio:checked')

I imagine this is a really basic bit of syntax, but I can't find it anywhere and I've tried lots of combination开发者_Python百科s with no luck......

Any help would be highly appreciated and apologies if this is really dumb but I'm very new to jQuery,

Nick

You can use

var checkedRadios = $('input:radio:checked', $question);

OR

var checkedRadios = $question.find('input:radio:checked');

This is called tree traversing, you can find more about tree traversing api in jQuery Documentation

The find method is used to search for elements under a given scope.

Use .find(), I think thats what your looking for!

$question.find('input:radio:checked');

EDIT I suggest skimming through jQuery API, http://api.jquery.com/category/traversing/tree-traversal/

I think your looking for

var checkedRadiosInsideQuestion = $question.find('input:radio:checked');

Try $('input:radio:checked', $question)...