FCKeditor_OnComplete is not suitable in my case

I know that there are a function call FCKeditor_OnComplete
but this function cannot fullfill my case,

for example, I use ajax to fillin my content, this function should put in the ajax function rather than FCKeditor_OnComplete
FCKeditorAPI.GetInstance('edt1').SetHTML('abc123');

so how can I check a Editor is fully loaded, if it is not complete then my function should wait until it is completed??