html input range thumb smooth movement

These are the things that affect the smoothness:

1. The width of the banner
2. The min/max range
3. The size of steps

So if you have:

1. 1000px wide range input
2. 0 - 1000 range
3. Step size of 1

Each step will be just 1px, and it will be quite smooth.

If you have:

1. 1000px wide range input
2. 0 -100 range
3. Step size of 25

It will snap between the allowable values, appearing less fluid.

This is really a feature of the interaction between your step size and your range, and provides useful feedback to the user on what values are acceptable.