selenium操作滚动条的几种方式

    WebElement element = dr.findElement(By.id("4"));
    ((JavascriptExecutor)dr).executeScript("arguments[0].scrollIntoView(true);", element);

    Actions a = new Actions(dr);
    a.moveToElement(dr.findElement(By.id("4"))).perform();

        Actions a = new Actions(dr);
        a.sendKeys(Keys.PAGE_DOWN).perform();
        try {
            Thread.sleep(3000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        a.sendKeys(Keys.PAGE_UP).perform();

        String js = "document.documentElement.scrollTop=10000";
        ((JavascriptExecutor)dr).executeScript(js);
        String js1 = "document.documentElement.scrollTop=0";
        ((JavascriptExecutor)dr).executeScript(js1);

        String js = "document.getElementById(\"su\").scrollTop=10000";
        ((JavascriptExecutor)dr).executeScript(js);
        String js1 = "document.getElementById(\"su\").scrollTop=0";
        ((JavascriptExecutor)dr).executeScript(js1);