Yes..! I agree with the Dieter's approach to get the map from the HTML page.
My suggestion is : use pagination or smart fetch, instead of displaying or editing all the rows.
1. Limit the number of rows in each page to 10 or 15.
2. Do not try to manage list of too many records in javascript, if so the browser will get hung & throws "Script Error"
Rgds
Mahesh PS