How to get caret position within contenteditable div with html child elements?

Question

I am working with a contenteditable div that will have the option to have inline html elements such as tags in the text flow.

At certain points I need to grab the caret position but have found that with the example code the position returned is incorrect if the caret is after an html child element.

I need a cross browser solution that will allow me to store the position of the caret so that it can be restored a split second later even with the presence of html elements in the text flow.

Example:

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;
}

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

div{width:300px; height:100px; border:solid 1px #DDD;}
div a{background:#333; color:#FFF;}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.6.4/jquery.min.js"></script>
<div contenteditable=true>
    some example text <a>anchor tag</a>&nbsp;
</div>

Original JSFiddle: http://jsfiddle.net/wPYMR/2/

Jena

What happens (or can happen) to the contents of the div during this split second? – Groundsheet

The last word type can be removed and the caret position corrected. – Jena

Answer 1

I've answered a very similar question here: Editing Iframe Content in IE - problem in maintaining text selection

Here's a slightly simplified version of that answer:

If you're not changing the contents of the contenteditable element then the following functions will do. Call saveSelection() before doing whatever you need to do and restoreSelection() afterwards. If you are changing the content, I'd suggest using my Rangy library's save/restore selection module.

var saveSelection, restoreSelection;
if (window.getSelection) {
    // IE 9 and non-IE
    saveSelection = function() {
        var sel = window.getSelection(), ranges = [];
        if (sel.rangeCount) {
            for (var i = 0, len = sel.rangeCount; i < len; ++i) {
                ranges.push(sel.getRangeAt(i));
            }
        }
        return ranges;
    };

    restoreSelection = function(savedSelection) {
        var sel = window.getSelection();
        sel.removeAllRanges();
        for (var i = 0, len = savedSelection.length; i < len; ++i) {
            sel.addRange(savedSelection[i]);
        }
    };
} else if (document.selection && document.selection.createRange) {
    // IE <= 8
    saveSelection = function() {
        var sel = document.selection;
        return (sel.type != "None") ? sel.createRange() : null;
    };

    restoreSelection = function(savedSelection) {
        if (savedSelection) {
            savedSelection.select();
        }
    };
}

Example use:

var sel = saveSelection();
// Do stuff here
restoreSelection(sel);

Groundsheet

how could this be applied to a single contenteditable div? Will this wokr when the contenteditable element has child elements? – Jena

@TimDown how this answer could help to get a caret position ? – Cribwork

Answer 2

        var display = $("#autocomplete");
        var editArea = $('#editArea');    
        console.log(e.target.selectionStart);           
        var pos = $("#editArea").caret();
        var offset = editArea.offset();
        // now you can use left, top(they are relative position)
        display.css({
            left: offset.left + 10,
            top:  offset.top + 13,
            color : "#449"
        })
        display.toggleClass("show");
        return false;

Demi