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When the design mode is on of an iframe body then if we press the enter key we a div is appended to the document body like this:



Which is pretty much good for my use case as i am working on a text editor with a support for code block and blockquote along with bold,italics,underline.

My approach to apply Blockquote and CodeBlock is that i have defined a CSS and would add the classes to the respective div/code element

In order to apply the classes on the div, i need to know that where exactly is my caret at . So for example i am in the body and added some text for blockquote then how can i know at which child element (div) holds my text to be formatted.

What I have tried:

var editor = document.getElementById("rtf-iframe").contentWindow.document.body;
editor.document.designMode = 'On';
var editor = document.getElementById("rtf-iframe").contentWindow.document.body;

I tried it via a click, whenever i click on the editor i can get the position of the child clicked :-

var currentLineClicked;

function setIndexOfClicked() {
    for (var i = 0, len = editor.children.length; i < len; i++)
            editor.children[i].onclick = function(){
                //   alert(index)  ;
                  currentLineClicked =index;
                  console.log("clicked div index is :"+currentLineClicked);  


After that i can successfully add a class to this div :

function applyBlockquote(){

    var currentIndex = currentLineClicked;

    editor.children[currentIndex].className = "bquote";


But what if a user adds some extra children in the body by pressing enter ? I tried playing with the MutationObserver to detect what kind of changes are being done in the Node but couldn't find how to get the current position of the caret/cursor ?

// Select the node that will be observed for mutations
var targetNode = document.getElementById('some-id');

// Options for the observer (which mutations to observe)
var config = { attributes: true, childList: true, subtree: true };

// Callback function to execute when mutations are observed
var callback = function(mutationsList, observer) {
    for(var mutation of mutationsList) {
        if (mutation.type == 'childList') {
            console.log('A child node has been added or removed.');
        else if (mutation.type == 'attributes') {
            console.log('The ' + mutation.attributeName + ' attribute was modified.');

// Create an observer instance linked to the callback function
var observer = new MutationObserver(callback);

// Start observing the target node for configured mutations
observer.observe(targetNode, config);

// Later, you can stop observing

A very close reference/example to my idea is this Markdown Editor :

I can see that a hidden text area is being used here.(Image of Inspected Element)

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