I have a question ,does the battle tab change every few minuites I was attacking a player on my battle tab then I went to repair my hull then when I went back he wasent on the battle tab ,has this happend to anyone else?

Thats the way it is.

so theres no way to keep attackin the same person

No the battle tab is set up so you can only attack a person once, if you have to stop to pay to repair your ship they will go away off your battle tab. To be able to keep attacking after you use up all your hull you have to use repair nanodrones or a trimark emblem or simular artifact without clicking out of the attack screen.

Thank God for that. Imagine how many times you'd be disabled daily if that weren't the case.

There is a way around that though. If you open a second browser tab to GL you can toggle back and forth between the tabs. Keep one tab on your target and the second on your ship screen. I have personally managed to attack 3 people at the same time on separate browser tabs with this method.