The jQuery UI Slider
This page demonstrates the jQuery UI range slider for setting values. In this case I'm not using the values for anything, just demonstrating how the UI range slider is used in conjunction with a number input box. If you're using the sliders to set variables for, say, a calculation or to set HTML parameters you have to pre-determine the max and min, however, you can exceed or fall short these presets using the number input on the left.
As an alternative to the UI slider you can use the CSS3 slider (click
Demo for a demonstration). I don't really have a preference between the two in terms of functionality but I do find the UI version easier to work with, though that's probably just down to familiarity.