jQuery best practice. patterns/anti patterns

gistfile1.js

//bad
$("#agree").bind("change", function() {
  if ($("input[type=submit]").hasClass("disabled")) {
     $("input[type=submit]").removeClass("disabled");
  } else {
     $("input[type=submit]").addClass("disabled");
  }
});

//good
$("#agree").bind("change", function() {
  var $input = $("input[type=submit]"),
      isDisabled = $input.hasClass("disabled");
  $input.toggleClass("disabled", isDisabled);
});
   
//ok 
function doSomething(el){console.log(el)};
$.each([3,4],doSomething);

//better if >= ie9
function doSomething(el){console.log(el)};
[3,4].forEach(doSomething);

-> only $.each if loop through jquery list of objects.

//nope
$("li").forEach(func)

//yes
$("li").each(func)

//what if its an array of object and you want to access value of each object certain prop
$.each([{x:3},{x:4}],doSomething); // 0, 1
[{x:3},{x:4}].forEach(doSomething);