http://www.tutorialsteacher.com/csharp/csharp-tutorials
or DotnetPerls or SitePoint
OR
http://www.tutorialspoint.com/asp.net/asp.net_life_cycle.htm
OR YOUTUBE
Execute C# online
https://www.tutorialspoint.com/csharp/index.htm
JSFiddle for execute JS, HTML, CSS online