like
@just21 mentioned, you can buy it and chart with excel or anything that can process a time series..
https://www.tickdata.com/product/historical-futures-data/
http://www.portaracqg.com/databaseall.php
I know you can chart the old historical contracts with CQG, like if I wanted to see GCEQ15 for example, I can enter that and see a daily chart with the default QTrader enablements (the history by default is 24 months I believe)... but if you want to go further back you need to subscribe/enable the older historical data which $$$... since you want web based, i tested on CQGm and that doesnt seem to work that way...
I personally use tickdata because of their cost, and I have no complains about their data (other than their resolution, as their old stuff goes down to sec only... )
another suggestion would be that you can grab the data from IQFeed using Qcollector Expert... something else I've done as well... you'll end up with a file you can pass to whatever program you want...