[Selenium]怎样验证页面是否有无变化

验证方法：将两次的Dom结构进行对比

        String beforeStr = (String) SeleniumUtil.getInnerHTML(page.getDriver(), page.getDLGDataColumnSetting());        
        el.click();
        String newStr = (String) SeleniumUtil.getInnerHTML(page.getDriver(), page.getDLGDataColumnSetting());
        Assert.assertEquals(newStr, beforeStr, "There are some changes.");