Get caret position in contentEditable div

Question

I'm finding tons of good, crossbrowser anwers on how to SET the cursor or caret position in a contentEditable DIV, but none on how to GET or find its position...

What I want to do is know the position of the caret within this div, on keyup.

So, when the user is typing text, I can at any point know its cursor's position within the div.

EDIT: I'm looking for the INDEX within the div contents (text), not the cursor coordinates.

<div id="contentBox" contentEditable="true"></div>

$('#contentbox').keyup(function() { 
    // ... ? 
});

Answer 1

The following code assumes:

• There is always a single text node within the editable <div> and no other nodes
• The editable div does not have the CSS white-space property set to pre

Code:

function getCaretPosition(editableDiv) {
  var caretPos = 0,
    sel, range;
  if (window.getSelection) {
    sel = window.getSelection();
    if (sel.rangeCount) {
      range = sel.getRangeAt(0);
      if (range.commonAncestorContainer.parentNode == editableDiv) {
        caretPos = range.endOffset;
      }
    }
  } else if (document.selection && document.selection.createRange) {
    range = document.selection.createRange();
    if (range.parentElement() == editableDiv) {
      var tempEl = document.createElement("span");
      editableDiv.insertBefore(tempEl, editableDiv.firstChild);
      var tempRange = range.duplicate();
      tempRange.moveToElementText(tempEl);
      tempRange.setEndPoint("EndToEnd", range);
      caretPos = tempRange.text.length;
    }
  }
  return caretPos;
}

#caretposition {
  font-weight: bold;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<div id="contentbox" contenteditable="true">Click me and move cursor with keys or mouse</div>
<div id="caretposition">0</div>
<script>
  var update = function() {
    $('#caretposition').html(getCaretPosition(this));
  };
  $('#contentbox').on("mousedown mouseup keydown keyup", update);
</script>

Answer 2

A few wrinkles that I don't see being addressed in other answers:

1. the element can contain multiple levels of child nodes (e.g. child nodes that have child nodes that have child nodes...)
2. a selection can consist of different start and end positions (e.g. multiple chars are selected)
3. the node containing a Caret start/end may not be either the element or its direct children

Here's a way to get start and end positions as offsets to the element's textContent value:

// node_walk: walk the element tree, stop when func(node) returns false
function node_walk(node, func) {
  var result = func(node);
  for(node = node.firstChild; result !== false && node; node = node.nextSibling)
    result = node_walk(node, func);
  return result;
};

// getCaretPosition: return [start, end] as offsets to elem.textContent that
//   correspond to the selected portion of text
//   (if start == end, caret is at given position and no text is selected)
function getCaretPosition(elem) {
  var sel = window.getSelection();
  var cum_length = [0, 0];

  if(sel.anchorNode == elem)
    cum_length = [sel.anchorOffset, sel.extentOffset];
  else {
    var nodes_to_find = [sel.anchorNode, sel.extentNode];
    if(!elem.contains(sel.anchorNode) || !elem.contains(sel.extentNode))
      return undefined;
    else {
      //var anchor_cum_length = 0;
      //var extent_cum_length = 0;
      var found = [0,0];
      var i;
      node_walk(elem, function(node) {
        for(i = 0; i < 2; i++) {
          if(node == nodes_to_find[i]) {
            found[i] = true;
            if(found[i == 0 ? 1 : 0])
              return false; // all done
          }
        }

        if(node.textContent && !node.firstChild) {
          for(i = 0; i < 2; i++) {
            if(!found[i])
              cum_length[i] += node.textContent.length;
          }
        }
      });
      cum_length[0] += sel.anchorOffset;
      cum_length[1] += sel.extentOffset;
    }
  }
  if(cum_length[0] <= cum_length[1])
    return cum_length;
  return [cum_length[1], cum_length[0]];
}

Answer 3

This one works for me:

function getCaretCharOffsetInDiv(element) {
    var caretOffset = 0;
    if (typeof window.getSelection != "undefined") {
        var range = window.getSelection().getRangeAt(0);
        var preCaretRange = range.cloneRange();
        preCaretRange.selectNodeContents(element);
        preCaretRange.setEnd(range.endContainer, range.endOffset);
        caretOffset = preCaretRange.toString().length;
    }
    else if (typeof document.selection != "undefined" && document.selection.type != "Control")
    {
        var textRange = document.selection.createRange();
        var preCaretTextRange = document.body.createTextRange();
        preCaretTextRange.moveToElementText(element);
        preCaretTextRange.setEndPoint("EndToEnd", textRange);
        caretOffset = preCaretTextRange.text.length;
    }
    return caretOffset;
} 

the calling line depends on event type, for key event use this:

getCaretCharOffsetInDiv(e.target) + ($(window.getSelection().getRangeAt(0).startContainer.parentNode).index());

for mouse event use this:

getCaretCharOffsetInDiv(e.target.parentElement) + ($(e.target).index())

on these two cases I take care for break lines by adding the target index

Answer 4

Try this:

Caret.js Get caret postion and offset from text field

https://github.com/ichord/Caret.js

demo: http://ichord.github.com/Caret.js

Answer 5

//global savedrange variable to store text range in
var savedrange = null;

function getSelection()
{
    var savedRange;
    if(window.getSelection && window.getSelection().rangeCount > 0) //FF,Chrome,Opera,Safari,IE9+
    {
        savedRange = window.getSelection().getRangeAt(0).cloneRange();
    }
    else if(document.selection)//IE 8 and lower
    { 
        savedRange = document.selection.createRange();
    }
    return savedRange;
}

$('#contentbox').keyup(function() { 
    var currentRange = getSelection();
    if(window.getSelection)
    {
        //do stuff with standards based object
    }
    else if(document.selection)
    { 
        //do stuff with microsoft object (ie8 and lower)
    }
});

Note: the range object its self can be stored in a variable, and can be re-selected at any time unless the contents of the contenteditable div change.

Reference for IE 8 and lower: http://msdn.microsoft.com/en-us/library/ms535872(VS.85).aspx

Reference for standards (all other) browsers: https://developer.mozilla.org/en/DOM/range (its the mozilla docs, but code works in chrome, safari, opera and ie9 too)

Answer 6

function getCaretPosition() {
    var x = 0;
    var y = 0;
    var sel = window.getSelection();
    if(sel.rangeCount) {
        var range = sel.getRangeAt(0).cloneRange();
        if(range.getClientRects()) {
        range.collapse(true);
        var rect = range.getClientRects()[0];
        if(rect) {
            y = rect.top;
            x = rect.left;
        }
        }
    }
    return {
        x: x,
        y: y
    };
}