IE浏览器下记住文本框的光标位置的代码

//#region --文本框TextArea光标相关
 var Pos = {
     //IE版本号
     getIEVer: function() {
         var match = navigator.appVersion.match(/MSIEs+d+.0;/);
         if (match == null) return -1;
         return +match[0].match(/d+/)[0];
     },
     getPos: function(textBox) {
         if (document.selection) {
             var range = document.selection.createRange();
             var range_all = document.body.createTextRange();
             range_all.moveToElementText(textBox);
             for (start = 0; range_all.compareEndPoints("StartToStart", range) < 0; start++) {
                 range_all.moveStart('character', 1);
             }
             var range_all = document.body.createTextRange();
             range_all.moveToElementText(textBox);
             for (end = 0; range_all.compareEndPoints('StartToEnd', range) < 0; end++) {
                 range_all.moveStart('character', 1);
             }
             var selectionStart = start;
             var selectionEnd = end;
             //ie8-rn在move时会当成一个字符
             if (this.getIEVer() > 8) {
                 var s1 = textBox.value.substr(0, selectionStart);
                 var s2 = textBox.value.substr(0, selectionEnd);
                 var m1 = s1.match(/rn/g);
                 var m2 = s2.match(/rn/g);
                 if (m1 != null) selectionStart += m1.length;
                 if (m2 != null) selectionEnd += m2.length;
             }
             return [selectionStart, selectionEnd];
         }
         else {
             return [t.selectionStart, t.selectionEnd];
         }
     },
     setPos: function(textBox, a, b) {
         if (a && b) {
             if (!(document.selection)) {
                 textBox.setSelectionRange(a, b);
             }
             else {
                 var range = textBox.createTextRange();
                 range.moveEnd('character', -textBox.value.length);
                 range.moveEnd('character', b);
                 range.moveStart('character', a);
                 range.select();
                 textBox.scrollTop = textBox.scrollTop2;
 
             }
         }
     },
     insert: function(textBox, value) {
         var text = textBox.value;
         var a = textBox.selectionStart2 || textBox.selectionStart;
         var b = textBox.selectionEnd2 || textBox.selectionEnd;
         var left = text.substr(0, a);
         var right = text.substr(b, text.length);
         b = a + value.length;
         textBox.value = left + value + right;
         this.setPos(textBox, b, b);
         this.savePos(textBox);
     },
     savePos: function(textBox) {
         if (document.selection) {
             var pos = this.getPos(textBox);
             textBox.selectionStart2 = pos[0];
             textBox.selectionEnd2 = pos[1];
             textBox.scrollTop2 = textBox.scrollTop;
         }
     }
 };
 
 jquery.fn.extend({
     rememberPos: function () {
         if (document.selection) {
             this.each(function (i, el) {
                 $(el).keyup(function () { Pos.savePos(el); });
                 $(el).mouseup(function () { Pos.savePos(el); });
                 $(el).focus(function () {
                     Pos.setPos(el, el.selectionStart2, el.selectionEnd2);
                 });
 
             });
         }
     }
 });
 
 $(function () {
    $("textarea").rememberPos();
 })