Nilzor,

 

Please try the following solution. Just modify it to fit your requirements.

 

function InsertNewTable()
   {
    // get the cute editor instance
    var editor = document.getElementById('<%=Editor1.ClientID%>'); 
    
    //Get the editor content 
    var editdoc=editor.GetDocument();
       
    var oNewTable = editdoc.createElement("TABLE");
    var td=editor.SearchSelectionElement("TD");
    if(td==null)
    {
     //insert the table into the editor directly
     editor.InsertElement(oNewTable);     
    }
    else
    {
     var table=Table_GetTable(td);
     table.parentNode.appendChild(oNewTable);
    }
   }