help me!

my fckeditor version is 2.x .Now I want to get editorare's content value via javascript.following is my code:
var oEditor = FCKeditorAPI.GetInstance('content') ;
var text=oEditor.GetXHTML(true);
above script can run successfully in IE envirement.but in firefox envirement.it reports errors:
FCKeditor_OnComplete(Object Name=content Status=2 EditMode=0 HasFocus=false)QY8.jsp （行 55）
WaitForActive(Object Name=content Status=2 EditMode=0 HasFocus=false, 1)fckedito...r=Default （行 232）
FCKDataProcessor()("OnStatusChange", 1)fckedito..._gecko.js （行 29）
InitializeBehaviors()(1)fckedito..._gecko.js （行 31）
_FCK_EditingArea_OnLoad()fckedito..._gecko.js （行 31）
CancelEvent()()
I want to know whether this is fckeditor's bug.or my way is wrong.....please hep me!!
thank you!