1 (function($) { 2     $.fn.extend({ 3         insertAtCaret: function(myValue) { 4             var $t = $(this)[0]; 5               //IE 6             if (document.selection) { 7                 this.focus(); 8                 sel = document.selection.createRange(); 9                 sel.text = myValue;10                 this.focus();11             } else12             //!IE13             if ($t.selectionStart || $t.selectionStart == "0") {14                 var startPos = $t.selectionStart;15                 var endPos = $t.selectionEnd;16                 var scrollTop = $t.scrollTop;17                 $t.value = http://www.mamicode.com/$t.value.substring(0, startPos) + myValue + $t.value.substring(endPos, $t.value.length);18                 this.focus();19                 $t.selectionStart = startPos + myValue.length;20                 $t.selectionEnd = startPos + myValue.length;21                 $t.scrollTop = scrollTop;22             } else {23                 this.value += myValue;24                 this.focus();25             }26         }27     })28 })(jQuery);

IE下可以通过document.selection.createRange();来实现，而Firefox（火狐）浏览器则需要首先获取光标位置，然后对value进行字符串截取处理。

$(selector).insertAtCaret("value");