问题
I am currently working on a project which uses a custom scroll plugin (written by me) to allow an element to be scrolled in touch devices, as well as desktop browsers. Everything is working correctly (including velocity and deceleration a la iOS).
However, the only problem that remains is calculating the top (or left) position of the scrollbar when a user scrolls. I have calculated the height of the scrollbar with the following formular:
Math.round((container.height() / content.height()) * 100);
This seems to compute the correct height of the bar, but now I need a formular to work out by how much the scrollbar's position should be moved when the user scrolls. I have checked through Google and wasn't able to find much of use, and also searched here on SO and would welcome any comments.
I have the following data available for use in the formula:
- Container height
- Content height
- Current scroll position (
scrollTop) - Height of scrollbar
回答1:
position of the scrollbar should be calculated by this formula:
Math.round((scrollbar.height * scrollTop / content.height());
来源：https://stackoverflow.com/questions/10257421/custom-scrollbar-maths-in-jquery-javascript