range3.py

def set_range(el, val):
    # The adjustment helper to drag the slider thumb
    def adjust(deltax):
        if deltax < 0:
            deltax = int(math.floor(min(-1, deltax)))
        else:
            deltax = int(math.ceil(max(1, deltax)))
        ac = ActionChains(driver)
        ac.click_and_hold(None)
        ac.move_by_offset(deltax, 0)
        ac.release(None)
        ac.perform()
    
    minval = float(el.get_attribute("min") or 0)
    maxval = float(el.get_attribute("max") or 100)
    v = max(0, min(1, (float(val) - minval) / (maxval - minval)))
    width = el.size["width"]
    target = float(width) * v
    
    ac = ActionChains(driver)
    
    # drag from min to max value, to ensure oninput event
    ac.move_to_element_with_offset(el, 0, 1)
    ac.click_and_hold()
    ac.move_by_offset(width, 0)
    
    # drag to the calculated position
    ac.move_to_element_with_offset(el, target, 1)
    
    ac.release()
    ac.perform()
    
    # perform a binary search and adjust the slider thumb until the value matches
    while True:
        curval = el.get_attribute("value")
        if float(curval) == float(val):
            return True
        prev_guess = target
        if float(curval) < float(val):
            minguess = target
            target += (maxguess - target) / 2
       else:
           maxguess = target
           target = minguess + (target - minguess) / 2
       deltax = target-prev_guess
       if abs(deltax) < 0.5
           break # cannot find a way, fallback to javascript.
    
       time.sleep(0.1) # Don't consume CPU too much
    
       adjust(deltax)
    
    # Finally, if the binary search algoritm fails to achieve the final value
    # we'll revert to the javascript method so at least the value will be changed
    # even though the browser events wont' be triggered.
    
     # Fallback
    driver.execute_script("arguments[0].value=arguments[1];", el, val)
    curval = el.get_attribute("value")
    if float(curval) == float(val):
        return True
    else:
        raise Exception("Can't set value %f for the element." % val)