function getEditorContents(){
   var oEditor = FCKeditorAPI.GetInstance("content");
   alert(oEditor.GetXHTML(true));
}
//向编辑器插入指定代码
function insertHTMLToEditor(codeStr){
   var oEditor = FCKeditorAPI.GetInstance("content");
   if (oEditor.EditMode==FCK_EDITMODE_WYSIWYG){
     oEditor.InsertHtml(codeStr);
   }else{
     return false;
   }
}
//统计编辑器中内容的字数
function getLength(){
   var oEditor = FCKeditorAPI.GetInstance("content");
   var oDOM = oEditor.EditorDocument;
   var iLength ;
   if(document.all){
     iLength = oDOM.body.innerText.length;
   }else{
     var r = oDOM.createRange();
     r.selectNodeContents(oDOM.body);
     iLength = r.toString().length;
   }
   alert(iLength);
}
//执行指定动作
function ExecuteCommand(commandName){
   var oEditor = FCKeditorAPI.GetInstance("content") ;
   oEditor.Commands.GetCommand(commandName).Execute() ;
}
//设置编辑器中内容
function SetContents(codeStr){
   var oEditor = FCKeditorAPI.GetInstance("content") ;
   oEditor.SetHTML(codeStr) ;
}

本文来自CSDN博客，出处：http://blog.csdn.net/impeller/archive/2008/03/05/2152195.aspx