IE下记住文本框的光标位置

方法一:

 1 //#region --文本框TextArea光标相关

 2 var Pos = {

 3     //IE版本号

 4     getIEVer: function() {

 5         var match = navigator.appVersion.match(/MSIE\s+\d+.0;/);

 6         if (match == null) return -1;

 7         return +match[0].match(/\d+/)[0];

 8     },

 9     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-\r\n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(/\r\n/g);

                 var m2 = s2.match(/\r\n/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();

 }) 

 方法二:

其实这是一个误区,其实我们根本就没有兴趣知道光标的具体位置,我们的目的一般有两个

1.在光标处插入字符

2.记住光标位置,在重获焦点时还原光标位置

 所以我们只需要textBox.selectRange=document.selection.createRange().duplicate();将选取区间复制一份保存下来

1.在光标处插入字符textBox.selectRange.text="xxxx";

2.记住光标位置,在重获焦点时还原光标位置textBox.selectRange.select();

是不是相当简单