How should I play against limpers? When I play online I play little aggressive so people start limping so how should I deal with this?
This question is similar to... What do I do if people give me money?
Limpers are the easiest to play against. Raises and bets can cause you to make bad decisions (folding wrong or giving more money wrong), but limping doesn't do anything. Against limpers, they are literally giving you the option to limp your speculative hands and raise your strong hands every time.
I think you are probably talking about live games, people don't limp online anymore. In live games, we have fish-central... It's limp-call 8x BB all day long. I can literally Raise my JJ to $20 (1/2 table) against 5 limpers and have probably one of them call me with 86o. Usually a C-Bet either makes them fold or they will call you with a smaller pair. Rarely they will hit a bigger pair so get ready to slow down if you see an overcard. They won't usually reraise or bet into you cause they are bad passive players, so you lose the minimum and generally win the maximum against them.
It's literally the ideal situation to play against a field of passive limp/check-call players.
raising 3x plus 1 BB per limper to isolate, which should get the weak hands out, so if there is 5 limpers before you raise 8x the big blind. Like others have said play tight, Bet Big with your good hands and small as a bluff. If you get raised after a cbet by a limper postflop, depending on your holding usually best to fold as theyre holding a combo of two pair most of the time.
Playing against limpers is easy. Play tight pre-flop. Wait for good hands. When you have a good hand raise as large as they are willing to call (usually that is quite large). What happens then is when you are involved in pots, the pot is big and you have a stronger range than the others. You will have a big advantage.