jQuery this selector function and limitations

Question

I need help understanding $(this). Is it possible to narrow the focus of "this" within the parentheses or does "this" preclude the use of any other attributes?

For example: I don't understand why this code:

$(this).children("div")

can't be rewritten like this:

$(this + " div")

without having to resort to something like:

$('#'+$(this).attr("id")+ " div")

Also, can you point me to 'this' in the jQuery documentation? It is difficult to use 'this' as a search term for obvious reasons.

Answer 1

this isn't a jQuery "thing", but a basic JavaScript one. It can't be re-written the way you have in examples because it's an object, in particular either a DOM element or a jQuery object (depending on what context you're in). So if you did this:

 $(this + " div")

What you'd really be doing is calling .toString() on this to concatenate the strings, resulting in:

 $("[object Object] div")

....which isn't a valid selector.