Use variables or "inject" jquery selectors when chaining?

Question

Hi,

is it better to do this (regarding performance, not readability...):

$('a.updateCartButton').click(function() {
  $('form[name=updateCartForm]').attr('action', $(this).attr('href') + '#' + $('img[id^=iconUpdateArticle]').attr('id')).submit();
  return false;
});

or this:

$('a.updateCartButton').click(function() {
  var actionHref = $(this).attr('href');
  var buttonId = $('img[id^=iconUpdateArticle]').attr('id');
  $('form[name="updateCartForm"]').attr('action', actionHref + '#' +buttonId).submit();
  return false;
});

Maybe someone could also explain to me how I can write a test case for something like this in jQuery Tester? Then I don't have to ask questions like this in the future... ;)

Thanks!

Answer 1

Either one is fine, you're talking about the performance of variable assignment, quite possibly the fastest feature in any language. The difference between:

var a = 1;
var b = 2;
return a + b;

versus:

return 1 + 2;

Should be close to nil for all modern day languages.