需求是获取某元素的内容，然后将该内容插入到文本框当前的光标位置

(function($) {                $.fn.extend({                    insertAtCaret: function(myValue) {                        var $t = $(this)[0];                        if (document.selection) {                            this.focus();                            sel = document.selection.createRange();                            sel.text = myValue;                            this.focus();                        }                        else                        if ($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;                        }                        else {                            this.value += myValue;                            this.focus();                        }                    }                })            })(jQuery);

 使用方法

$('#demo').insertAtCaret('hello');