Swap two html elements and preserve event listeners on them

Question

There are similar questions, but all the answers are for swapping html elements only for the content inside.

I need to swap two divs, with lots of content in them (tables, select boxes, inputs, etc.). The elements have event listeners on them, so I need to preserve them after swapping the main divs.

I have access to jQuery 1.5. So answers with it are OK.

Solution 1

To swap two divs without losing event handlers or breaking DOM references, you can just move them in the DOM. The key is NOT to change the innerHTML because that recreates new DOM nodes from scratch and all prior event handlers on those DOM objects are lost.

But, if you just move the DOM elements to a new place in the DOM, all events stay attached because the DOM elements are only reparented without changing the DOM elements themselves.

Here's a quick function that would swap two elements in the DOM. It should work with any two elements as long as one is not a child of the other:

function swapElements(obj1, obj2) {
    // create marker element and insert it where obj1 is
    var temp = document.createElement("div");
    obj1.parentNode.insertBefore(temp, obj1);

    // move obj1 to right before obj2
    obj2.parentNode.insertBefore(obj1, obj2);

    // move obj2 to right before where obj1 used to be
    temp.parentNode.insertBefore(obj2, temp);

    // remove temporary marker node
    temp.parentNode.removeChild(temp);
}

You can see it work here: http://jsfiddle.net/jfriend00/NThjN/

---

And here's a version that works without the temporary element inserted:

function swapElements(obj1, obj2) {
    // save the location of obj2
    var parent2 = obj2.parentNode;
    var next2 = obj2.nextSibling;
    // special case for obj1 is the next sibling of obj2
    if (next2 === obj1) {
        // just put obj1 before obj2
        parent2.insertBefore(obj1, obj2);
    } else {
        // insert obj2 right before obj1
        obj1.parentNode.insertBefore(obj2, obj1);

        // now insert obj1 where obj2 was
        if (next2) {
            // if there was an element after obj2, then insert obj1 right before that
            parent2.insertBefore(obj1, next2);
        } else {
            // otherwise, just append as last child
            parent2.appendChild(obj1);
        }
    }
}

Working demo: http://jsfiddle.net/jfriend00/oq92jqrb/

Solution 2

This is a simpler function for swapping two elements without actually reloading the element...

function swapElements(obj1, obj2) {
    obj2.nextSibling === obj1
    ? obj1.parentNode.insertBefore(obj2, obj1.nextSibling)
    : obj1.parentNode.insertBefore(obj2, obj1); 
}

Note: if the obj1 has an embedded video like YouTube, it will not reload when swapped. It's just the position of the elements that changed.

Solution 3

My simple function seems to be the shortest and most widely compatible. It doesn't need placeholders or reload elements or anything messy like that:

function swapElements(el1, el2) {
    var p2 = el2.parentNode, n2 = el2.nextSibling
    if (n2 === el1) return p2.insertBefore(el1, el2)
    el1.parentNode.insertBefore(el2, el1);
    p2.insertBefore(el1, n2);
}

Solution 4

If you keep track of the two elements' parentNodes and the nextSibling of one, you can swap two elements with their children without any temporary placeholders.

If the second element is an only child, or the last child of its parent, its replacement is (properly) appended to the parent.

function swap(a, b){
    var p1= a.parentNode, p2= b.parentNode, sib= b.nextSibling;
    if(sib=== a) sib= sib.nextSibling;
    p1.replaceChild(b, a);
    if(sib) p2.insertBefore(a, sib);
    else p2.appendChild(a);
    return true;
}

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