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Start your free trialJames Nguyen
Courses Plus Student 6,841 Pointsthis video is something wrong because of nextLi= li.nextElementSibling then ul.insertBefore(nextLi,li) is the same. so
so it is the same. I think we should use afterNextLi = nextLi.nextElementSibling then ul.insertBefore(afterNextLi, li) that will make sense
2 Answers
Owen Bell
8,060 PointsI think you're a bit confused as to how the .insertBefore
method works. Check the MDN documentation for more clarification. You should see the following syntax template:
var insertedNode = parentNode.insertBefore(newNode, referenceNode);
The first parameter of .insertBefore
specifies the element to be moved; the second specifies the element that the first is to be inserted before.
Guil's code selects the list item whose 'Down' button was clicked and stores it in the li
variable, then selects the next list item (if it exists) and stores that in the nextLi
variable (undefined
if no next item exists). Finally, he selects the entire list and stores it in ul
. The conditional statement then checks if nextLi
is truthy; in other words, does a next list element exist, or is the element stored in li
the final list item? If there is a next item, the following code block runs:
ul.insertBefore(nextLi, li);
This removes the next list element from its current position and inserts it before the list item whose 'Down' button was clicked - the result of this is that the next list item moves upwards whilst the clicked item moves downwards.
James Nguyen
Courses Plus Student 6,841 Pointsthank you verry much I am sorry about that