Proper use of laptop

Yes, it's fine. However, over time, this will increase the wear-and-tear on your battery so if you plan on staying plugged in for a long time, it might be better to simply remove the battery and run solely on AC power.

An important thing to note is that you should have a reliable AC supply before you do this, or else you might lose all your work if you lose power.

Thank u vry much..... 

So v can use laptop on battery as many times we want right???
There is no limit on it??

Uh... your battery will wear down over time and lose capacity.

For example, a new battery will hold 5 hours of charge. One year later, it will hold 3.5-4 hours of charge. After 4 years, it will hold 1 hour of charge. These numbers are just made-up, but your battery will fall below this curve, losing its capacity more quickly due to the higher current flowing into it.

I don't guess it ever occurred to me to use a laptop without a battery. So a totally unused battery would be able to hold a higher charge than one used/charged on a regular basis? Neat!

Well, not totally unused. To maximize battery life, you should discharge and recharge it fully about once a week. For the rest of the week, you can keep it somewhere around half-charged.