jQuery.fn.extend({
    set_caret: function(){
        if(!$.browser.msie) return;
        var initSetCaret = function(){this.caretPos = document.selection.createRange().duplicate()};
        this.click(initSetCaret).select(initSetCaret).keyup(initSetCaret);
    }, 
    insert_caret:function(textFeildValue){
        var textObj = this[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;
        }
    }
})

前台要用就比较简单了,  只需要这样写:
<div>
                <h3>
                    这里可以放标题
                h3>
                <div>
                    这里是一些主要的内容
                    <dl>
                        <dt>Hello worlddt>
                        <dd>
                            hahahadd>
                    dl>
                    这个实验在沙加的神舟本上完成
                div>
                <div>
                    <a href="javascript:void(0);">[收起]a> <a
                        href="javascript:void(0);">[展开]a>
                div>
            div>

样式就省略了, 大家可以自己写, 最后发两个效果图: