jQuery.extend({         /**         * 清除当前选择内容         */        unselectContents: function(){             if(window.getSelection)                 window.getSelection().removeAllRanges();             else if(document.selection)                 document.selection.empty();         }     });     jQuery.fn.extend({         /**         * 选中内容         */        selectContents: function(){             $(this).each(function(i){                 var node = this;                 var selection, range, doc, win;                 if ((doc = node.ownerDocument) &&                     (win = doc.defaultView) &&                     typeof win.getSelection != 'undefined' &&                     typeof doc.createRange != 'undefined' &&                     (selection = window.getSelection()) &&                     typeof selection.removeAllRanges != 'undefined')                 {                     range = doc.createRange();                     range.selectNode(node);                     if(i == 0){                         selection.removeAllRanges();                     }                     selection.addRange(range);                 }                 else if (document.body &&                          typeof document.body.createTextRange != 'undefined' &&                          (range = document.body.createTextRange()))                 {                     range.moveToElementText(node);                     range.select();                 }             });         },         /**         * 初始化对象以支持光标处插入内容         */        setCaret: function(){             if(!$.browser.msie) return;             var initSetCaret = function(){                 var textObj = $(this).get(0);                 textObj.caretPos = document.selection.createRange().duplicate();             };             $(this)             .click(initSetCaret)             .select(initSetCaret)             .keyup(initSetCaret);         },         /**         * 在当前对象光标处插入指定的内容         */        insertAtCaret: function(textFeildValue){            var textObj = $(this).get(0);            if(document.all && textObj.createTextRange && textObj.caretPos){                var caretPos=textObj.caretPos;                caretPos.text = caretPos.text.charAt(caretPos.text.length-1) == '' ?                                    textFeildValue+'' : textFeildValue;            }            else if(textObj.setSelectionRange){                var rangeStart=textObj.selectionStart;                var rangeEnd=textObj.selectionEnd;                var tempStr1=textObj.value.substring(0,rangeStart);                var tempStr2=textObj.value.substring(rangeEnd);                textObj.value=tempStr1+textFeildValue+tempStr2;                textObj.focus();                var len=textFeildValue.length;                textObj.setSelectionRange(rangeStart+len,rangeStart+len);                textObj.blur();            }            else {                textObj.value+=textFeildValue;            }         }     });    