cursor.jquery.js

function setSelectionPlugin() {
    var _setSelectionRange, _getCursorPosition, support = (function() {
        var input = document.createElement('input'), result;
        result = {
            setSelectionRange: ('setSelectionRange' in input) || ('selectionStart' in input),
            createTextRange: ('createTextRange' in input) || ('selection' in document)
        };
        input = null;
        return result;
    }());

    if (support.setSelectionRange) {
        _setSelectionRange = function (start, end) {
            this.setSelectionRange(start, end);
        }

        _getCursorPosition = function () {
            return this.selectionStart;
        }
    } else if (support.createTextRange) {
        _setSelectionRange = function (start, end) {
            var range = this.createTextRange();
            range.collapse();
            range.moveEnd('character', end);
            range.moveStart('character', start);
            range.select();
        }

        _getCursorPosition = function () {
            var el = this[0];
            var r = document.selection.createRange();
            if (!el || !r) {
                return 0;
            }
            var re = el.createTextRange(),
                rc = re.duplicate();
            re.moveToBookmark(r.getBookmark());
            rc.setEndPoint('EndToStart', re);

            return rc.text.length;
        }
    }
    support = null;

    return {
        setSelectionRange: function (start, end) {
            this.each(_setSelectionRange, [start, end])
        },
        setCursorPosition: function (start) {
            this.each(_setSelectionRange, [start, start])
        },
        getCursorPosition: function () {
            return this.length ? _getCursorPosition.call(this[0]) : -1;
        }
    };
}

$.fn.extend(setSelectionPlugin());