Get caret position in contentEditable div

Question

Hi,

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

//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 2

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, containerEl = null, 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;
}

$('#contentbox').keyup(function() { 
    alert(getCaretPosition(this));
});