// 在光标处插入字符串

    // myField    文本框对象

    // myValue 要插入的值

    function insertAtCursor(myField, myValue)

    {

        //IE support

        if (document.selection)

        {

            myField.focus();

            sel            = document.selection.createRange();

            sel.text    = myValue;

            sel.select();

        }

        //MOZILLA/NETSCAPE support

        else if (myField.selectionStart || myField.selectionStart == '0')

        {

            var startPos    = myField.selectionStart;

            var endPos        = myField.selectionEnd;

            // save scrollTop before insert

            var restoreTop    = myField.scrollTop;

            myField.value    = myField.value.substring(0, startPos) + myValue + myField.value.substring(endPos, myField.value.length);

            if (restoreTop > 0)

            {

                // restore previous scrollTop

                myField.scrollTop = restoreTop;

            }

            myField.focus();

            myField.selectionStart    = startPos + myValue.length;

            myField.selectionEnd    = startPos + myValue.length;

        } else {

            myField.value += myValue;

            myField.focus();

        }

    }

       function insertText() {

            var obj = document.getElementById("文本框");

            var str = "[#$%$#]插入的内容";

               if (document.selection) {

                   obj.focus();

                   var sel = document.selection.createRange();

                   sel.text = str;

               } else if (typeof obj.selectionStart === 'number' && typeof obj.selectionEnd === 'number') {

                   var startPos = obj.selectionStart;

                   var endPos = obj.selectionEnd;

                    var tmpStr = obj.value;

                    obj.value = tmpStr.substring(0, startPos) + str + tmpStr.substring(endPos, tmpStr.length);

                } else {

                    obj.value += str;

            }

        }

//jQuery光标处插入文本

        $(document).ready(function () {

            $("#btnInsert").click(function () {

                var obj = $("#txtquestion").get(0);

                var str = "[#$%$#]";

                if (document.selection) {

                    obj.focus();

                    var sel = document.selection.createRange();

                    sel.text = str;

                } else if (typeof obj.selectionStart === 'number' && typeof obj.selectionEnd === 'number') {

                    var startPos = obj.selectionStart;

                    var endPos = obj.selectionEnd;

                    var tmpStr = obj.value;

                    obj.value = tmpStr.substring(0, startPos) + str + tmpStr.substring(endPos, tmpStr.length);

                } else {

                    obj.value += str;

            });

        });

        (function ($) {

            $.fn.insertContent = function (myValue, t) {

                var $t = $(this)[0];

                if (document.selection) { //ie

                    this.focus();

                    var sel = document.selection.createRange();

                    sel.text = myValue;

                    this.focus();

                    sel.moveStart('character', -l);

                    var wee = sel.text.length;

                    if (arguments.length == 2) {

                        var l = $t.value.length;

                        sel.moveEnd("character", wee + t);

                        t <= 0 ? sel.moveStart("character", wee - 2 * t - myValue.length) : sel.moveStart("character", wee - t - myValue.length);

                        sel.select();

                    }

                } else if ($t.selectionStart || $t.selectionStart == '0') {

                    var startPos = $t.selectionStart;

                    var endPos = $t.selectionEnd;

                    var scrollTop = $t.scrollTop;

                    $t.value = $t.value.substring(0, startPos) + myValue + $t.value.substring(endPos, $t.value.length);

                    this.focus();

                    $t.selectionStart = startPos + myValue.length;

                    $t.selectionEnd = startPos + myValue.length;

                    $t.scrollTop = scrollTop;

                    if (arguments.length == 2) {

                        $t.setSelectionRange(startPos - t, $t.selectionEnd + t);

                        this.focus();

                    }

                }

                else {

                    this.value += myValue;

                    this.focus();

                }

            };

        })(jQuery);