Fckeditor编辑器内容长度限制统计实现方法

<script type="text/javascript" src="/editor/fckeditor.js"></script>
<script type="text/javascript">
<!--
var oFCKeditor = new FCKeditor( 'Content' ) ;
oFCKeditor.BasePath = "/editor/" ;
oFCKeditor.ToolbarSet = "User" ;
oFCKeditor.Value = '没有最好，只有更好，大家努力' ;
oFCKeditor.Height = 450 ;
oFCKeditor.Width = 660 ;
oFCKeditor.Create() ;
//-->
</script>
<input type="button" value="检测字数(包括HTML代码)" style="width:165px;" class="inputc" onClick="checklength()">
<script>

function checklength()
{
var Content;
var oEditor = FCKeditorAPI.GetInstance('Content') ;
Content=oEditor.GetXHTML(true)
alert("n当前: "+Content.length+" 个字符");
return false;
}
</script>

window.onload=function(){
function FCKeditor_OnComplete()
{
var editor = FCKeditorAPI.GetInstance('info') ;
editor.Events.AttachEvent('OnSelectionChange', editor_keydown);
}
function editor_keydown(editor)
{
var maxLength=3; //最大输入字数
content= $(editor.EditorDocument.body).text();
var len= content.length;
var $info =$('#info');//存放提示信息
if(len < maxLength){
.text("还可以输入 "+(maxLength-len)+"字");
}
if(len == maxLength){
$info.text("字数达到上限");
}
if(len > maxLength){
$info.text(" 输入字符超过"+maxLength+"个,请更改！");
}
}
FCKeditor_OnComplete()
}