static/tinymce/tiny_mce_src.js
function getRange() {
			var ieRange = selection.getRng(), domRange = dom.createRng(), element, collapsed, tmpRange, element2, bookmark, fail;

			// If selection is outside the current document just return an empty range
			element = ieRange.item ? ieRange.item(0) : ieRange.parentElement();
			if (element.ownerDocument != dom.doc)
				return domRange;

			collapsed = selection.isCollapsed();

			// Handle control selection
			if (ieRange.item) {
				domRange.setStart(element.parentNode, dom.nodeIndex(element));
				domRange.setEnd(domRange.startContainer, domRange.startOffset + 1);

				return domRange;
			}

			function findEndPoint(start) {
				var endPoint = getPosition(ieRange, start), container, offset, textNodeOffset = 0, sibling, undef, nodeValue;

				container = endPoint.node;
				offset = endPoint.offset;

				if (endPoint.inside && !container.hasChildNodes()) {
					domRange[start ? 'setStart' : 'setEnd'](container, 0);
					return;
				}

				if (offset === undef) {
					domRange[start ? 'setStartBefore' : 'setEndAfter'](container);
					return;
				}

				if (endPoint.position < 0) {
					sibling = endPoint.inside ? container.firstChild : container.nextSibling;

					if (!sibling) {
						domRange[start ? 'setStartAfter' : 'setEndAfter'](container);
						return;
					}

					if (!offset) {
						if (sibling.nodeType == 3)
							domRange[start ? 'setStart' : 'setEnd'](sibling, 0);
						else
							domRange[start ? 'setStartBefore' : 'setEndBefore'](sibling);

						return;
					}

					// Find the text node and offset
					while (sibling) {
						nodeValue = sibling.nodeValue;
						textNodeOffset += nodeValue.length;

						// We are at or passed the position we where looking for
						if (textNodeOffset >= offset) {
							container = sibling;
							textNodeOffset -= offset;
							textNodeOffset = nodeValue.length - textNodeOffset;
							break;
						}

						sibling = sibling.nextSibling;
					}
				} else {
					// Find the text node and offset
					sibling = container.previousSibling;

					if (!sibling)
						return domRange[start ? 'setStartBefore' : 'setEndBefore'](container);

					// If there isn't any text to loop then use the first position
					if (!offset) {
						if (container.nodeType == 3)
							domRange[start ? 'setStart' : 'setEnd'](sibling, container.nodeValue.length);
						else
							domRange[start ? 'setStartAfter' : 'setEndAfter'](sibling);

						return;
					}

					while (sibling) {
						textNodeOffset += sibling.nodeValue.length;

						// We are at or passed the position we where looking for
						if (textNodeOffset >= offset) {
							container = sibling;
							textNodeOffset -= offset;
							break;
						}

						sibling = sibling.previousSibling;
					}
				}

				domRange[start ? 'setStart' : 'setEnd'](container, textNodeOffset);
			};

			try {
				// Find start point
				findEndPoint(true);

				// Find end point if needed
				if (!collapsed)
					findEndPoint();
			} catch (ex) {
				// IE has a nasty bug where text nodes might throw "invalid argument" when you
				// access the nodeValue or other properties of text nodes. This seems to happend when
				// text nodes are split into two nodes by a delete/backspace call. So lets detect it and try to fix it.
				if (ex.number == -2147024809) {
					// Get the current selection
					bookmark = self.getBookmark(2);

					// Get start element
					tmpRange = ieRange.duplicate();
					tmpRange.collapse(true);
					element = tmpRange.parentElement();

					// Get end element
					if (!collapsed) {
						tmpRange = ieRange.duplicate();
						tmpRange.collapse(false);
						element2 = tmpRange.parentElement();
						element2.innerHTML = element2.innerHTML;
					}

					// Remove the broken elements
					element.innerHTML = element.innerHTML;

					// Restore the selection
					self.moveToBookmark(bookmark);

					// Since the range has moved we need to re-get it
					ieRange = selection.getRng();

					// Find start point
					findEndPoint(true);

					// Find end point if needed
					if (!collapsed)
						findEndPoint();
				} else
					throw ex; // Throw other errors
			}

			return domRange;
		}
function getRange() {
			var ieRange = selection.getRng(), domRange = dom.createRng(), element, collapsed, tmpRange, element2, bookmark, fail;

			// If selection is outside the current document just return an empty range
			element = ieRange.item ? ieRange.item(0) : ieRange.parentElement();
			if (element.ownerDocument != dom.doc)
				return domRange;

			collapsed = selection.isCollapsed();

			// Handle control selection
			if (ieRange.item) {
				domRange.setStart(element.parentNode, dom.nodeIndex(element));
				domRange.setEnd(domRange.startContainer, domRange.startOffset + 1);

				return domRange;
			}

			function findEndPoint(start) {
				var endPoint = getPosition(ieRange, start), container, offset, textNodeOffset = 0, sibling, undef, nodeValue;

				container = endPoint.node;
				offset = endPoint.offset;

				if (endPoint.inside && !container.hasChildNodes()) {
					domRange[start ? 'setStart' : 'setEnd'](container, 0);
					return;
				}

				if (offset === undef) {
					domRange[start ? 'setStartBefore' : 'setEndAfter'](container);
					return;
				}

				if (endPoint.position < 0) {
					sibling = endPoint.inside ? container.firstChild : container.nextSibling;

					if (!sibling) {
						domRange[start ? 'setStartAfter' : 'setEndAfter'](container);
						return;
					}

					if (!offset) {
						if (sibling.nodeType == 3)
							domRange[start ? 'setStart' : 'setEnd'](sibling, 0);
						else
							domRange[start ? 'setStartBefore' : 'setEndBefore'](sibling);

						return;
					}

					// Find the text node and offset
					while (sibling) {
						nodeValue = sibling.nodeValue;
						textNodeOffset += nodeValue.length;

						// We are at or passed the position we where looking for
						if (textNodeOffset >= offset) {
							container = sibling;
							textNodeOffset -= offset;
							textNodeOffset = nodeValue.length - textNodeOffset;
							break;
						}

						sibling = sibling.nextSibling;
					}
				} else {
					// Find the text node and offset
					sibling = container.previousSibling;

					if (!sibling)
						return domRange[start ? 'setStartBefore' : 'setEndBefore'](container);

					// If there isn't any text to loop then use the first position
					if (!offset) {
						if (container.nodeType == 3)
							domRange[start ? 'setStart' : 'setEnd'](sibling, container.nodeValue.length);
						else
							domRange[start ? 'setStartAfter' : 'setEndAfter'](sibling);

						return;
					}

					while (sibling) {
						textNodeOffset += sibling.nodeValue.length;

						// We are at or passed the position we where looking for
						if (textNodeOffset >= offset) {
							container = sibling;
							textNodeOffset -= offset;
							break;
						}

						sibling = sibling.previousSibling;
					}
				}

				domRange[start ? 'setStart' : 'setEnd'](container, textNodeOffset);
			};

			try {
				// Find start point
				findEndPoint(true);

				// Find end point if needed
				if (!collapsed)
					findEndPoint();
			} catch (ex) {
				// IE has a nasty bug where text nodes might throw "invalid argument" when you
				// access the nodeValue or other properties of text nodes. This seems to happend when
				// text nodes are split into two nodes by a delete/backspace call. So lets detect it and try to fix it.
				if (ex.number == -2147024809) {
					// Get the current selection
					bookmark = self.getBookmark(2);

					// Get start element
					tmpRange = ieRange.duplicate();
					tmpRange.collapse(true);
					element = tmpRange.parentElement();

					// Get end element
					if (!collapsed) {
						tmpRange = ieRange.duplicate();
						tmpRange.collapse(false);
						element2 = tmpRange.parentElement();
						element2.innerHTML = element2.innerHTML;
					}

					// Remove the broken elements
					element.innerHTML = element.innerHTML;

					// Restore the selection
					self.moveToBookmark(bookmark);

					// Since the range has moved we need to re-get it
					ieRange = selection.getRng();

					// Find start point
					findEndPoint(true);

					// Find end point if needed
					if (!collapsed)
						findEndPoint();
				} else
					throw ex; // Throw other errors
			}

			return domRange;
		}
Returns a W3C DOM compatible range object by using the IE Range API