Timeline does not run evenly

When I click on the play to see the animation the timeline does not run evenly … it’s going to give little jumps … how to solve this?

There is a preview feature for your animation if you press f11.
A little window will pop up, where you can see your animation, depending on the complexity of your scene and the hardware of your computer it may take a while to render but after that you should be able to see your animation in realtime