Can a single MutationObserver object observe multiple targets?

Question

I would like to use a MutationObserver object to observe changes to some of my DOM nodes.

The docs give an example of creating a MutationObserver object an

Answer 1

The observer will now be watching two targets - target and target2 per your definitions. No error will be thrown, and target will not be "unregistered" in favor of target2. No unexpected or other behaviors will be exhibited.

Here is a sample which uses the same MutationObserver on two contenteditable elements. To view this, delete the <span> node from each contenteditable element and view the behavior span across both observed elements.

<div id="myTextArea" contenteditable="true">
    <span contenteditable="false">Span A</span>
</div>

<div id="myTextArea2" contenteditable="true">
    <span contenteditable="false">Span B</span>
</div>

---

var observer = new MutationObserver(function(mutations) {
  mutations.forEach(function(mutation) {
      //console.log($(mutation.removedNodes)); // <<-- includes text nodes

      $(mutation.removedNodes).each(function(value, index) {
          if(this.nodeType === 1) {
              console.log(this)
          }
      });
  });
});

var config = { attributes: true, childList: true, characterData: true };

observer.observe($('#myTextArea')[0], config);

observer.observe($('#myTextArea2')[0], config);

JSFiddle Link - demo

Note that I have recycled the same config for this first demo, but, placing a new config will be exclusive to that observed element. Taking your example as defined in config2, if used on #myTextArea2, you'll not see the logged node per the configuration options, but notice that the observer for #myTextArea is unaffected.

JSFiddle Link - demo - configuration exclusiveness