输入新行时，如何获取插入符号在contentEditable div中的位置？

Question

I am making a rich text editor with UIWebview, which uses a contentEditable div. I want to get the caret's position in pixels. I have searched a lot, and I got the code below.

function getCaretClientPosition() {
  var x = 0, y = 0;
  var sel = window.getSelection();
  if (sel.rangeCount) {
    var range = sel.getRangeAt(0);
    if (range.getClientRects) {
      var rects = range.getClientRects();
      if (rects.length > 0) {
        x = rects[0].left;
        y = rects[0].top;
      }
    }
  }
  return { x: x, y: y };
}

The code above works well until I enter a newline. sel.getRangeAt(0) returns null, so the function can't return the right caret Y pixels.

Answer 1

Here is the code I am using to get the caret's top position by inserting a temp object and remove it:

function getCaretTopPosition() {
    document.execCommand('insertHTML', false, '<span id="hidden"></span>');
    var hiddenNode = document.getElementById('hidden');
    if (!hiddenNode) {
        return 0;
    }
    var topPosition = hiddenNode.offsetTop;
    hiddenNode.parentNode.removeChild(hiddenNode);
    return topPosition;
}

Answer 2

This solution fixes the newLine issue in WebKit.

function getCaretClientPosition() {
    var x = 0, y = 0;
    var sel = window.getSelection();
    if (sel.rangeCount) {

        var range = sel.getRangeAt(0);
        var needsToWorkAroundNewlineBug = (range.startContainer.nodeName.toLowerCase() == 'p'
                                           && range.startOffset == 0);

        if (needsToWorkAroundNewlineBug) {
            x = range.startContainer.offsetLeft;
            y = range.startContainer.offsetTop;
        } else {
            if (range.getClientRects) {
                var rects = range.getClientRects();
                if (rects.length > 0) {
                    x = rects[0].left;
                    y = rects[0].top;
                }
            }
        }
    }
    return { x: x, y: y };
}