Okay well Browser isn’t the best idea to use and will pretty much always be laggy. I suggest you try to use flash and look up ways to get it to work but steam is also a good program to use (Which is what i use). But if your lagging still, it could be because…
- Your Internet
- Your Hardware
- Game Options
If it may be because of internet, I suggest closing tabs, and monitoring where the wifi is being used in your household. Ethernet is a good solution for internet lag and will give you faster speeds.
If it may be because of your hardware, well there is only some solutions to that.
Solutions
- Close tabs that are taking up RAM.
- Upgrade your Hardware.
- (More if your PC is clogged up with programs and storage) Get some anti-virus program which can give you access to clean your computer for better gaming gameplay.
If it may be because of your game options, then i suggest you optimise your options to where it best suites you for no lag.
Hope this helps!