上一篇博文简要
在上一篇博文中已得知：使用 execute 向远程服务器发送请求会通过 webdriver 与浏览器交互，且发送已定义的命令常量可获得一些相关信息。
其中 execute 方法实现已经在上一篇博文中有实现说明。并且在我们已经知道 webdriver基类（selenium.webdriver.remote.webdriver）中，实现了操作页面元素的基本方法。
通过简单运用全面学习
假设现在需要打开百度，搜索“CSDN A757291228”该如何进行操作呢?
通过查找 webdriver基类（selenium.webdriver.remote.webdriver）找到了以下几个查找元素的方法：
def find_element_by_id(self, id_): """Finds an element by id. :Args: - id\_ - The id of the element to be found. :Returns: - WebElement - the element if it was found :Raises: - NoSuchElementException - if the element wasn't found :Usage: element = driver.find_element_by_id('foo') """ return self.find_element(by=By.ID, value=id_) def find_elements_by_id(self, id_): """ Finds multiple elements by id. :Args: - id\_ - The id of the elements to be found. :Returns: - list of WebElement - a list with elements if any was found. An empty list if not :Usage: elements = driver.find_elements_by_id('foo') """ return self.find_elements(by=By.ID, value=id_) def find_element_by_xpath(self, xpath): """ Finds an element by xpath. :Args: - xpath - The xpath locator of the element to find. :Returns: - WebElement - the element if it was found :Raises: - NoSuchElementException - if the element wasn't found :Usage: element = driver.find_element_by_xpath('//div/td[1]') """ return self.find_element(by=By.XPATH, value=xpath) def find_elements_by_xpath(self, xpath): """ Finds multiple elements by xpath. :Args: - xpath - The xpath locator of the elements to be found. :Returns: - list of WebElement - a list with elements if any was found. An empty list if not :Usage: elements = driver.find_elements_by_xpath("//div[contains(@class, 'foo')]") """ return self.find_elements(by=By.XPATH, value=xpath) def find_element_by_link_text(self, link_text): """ Finds an element by link text. :Args: - link_text: The text of the element to be found. :Returns: - WebElement - the element if it was found :Raises: - NoSuchElementException - if the element wasn't found :Usage: element = driver.find_element_by_link_text('Sign In') """ return self.find_element(by=By.LINK_TEXT, value=link_text) def find_elements_by_link_text(self, text): """ Finds elements by link text. :Args: - link_text: The text of the elements to be found. :Returns: - list of webelement - a list with elements if any was found. an empty list if not :Usage: elements = driver.find_elements_by_link_text('Sign In') """ return self.find_elements(by=By.LINK_TEXT, value=text) def find_element_by_partial_link_text(self, link_text): """ Finds an element by a partial match of its link text. :Args: - link_text: The text of the element to partially match on. :Returns: - WebElement - the element if it was found :Raises: - NoSuchElementException - if the element wasn't found :Usage: element = driver.find_element_by_partial_link_text('Sign') """ return self.find_element(by=By.PARTIAL_LINK_TEXT, value=link_text) def find_elements_by_partial_link_text(self, link_text): """ Finds elements by a partial match of their link text. :Args: - link_text: The text of the element to partial match on. :Returns: - list of webelement - a list with elements if any was found. an empty list if not :Usage: elements = driver.find_elements_by_partial_link_text('Sign') """ return self.find_elements(by=By.PARTIAL_LINK_TEXT, value=link_text) def find_element_by_name(self, name): """ Finds an element by name. :Args: - name: The name of the element to find. :Returns: - WebElement - the element if it was found :Raises: - NoSuchElementException - if the element wasn't found :Usage: element = driver.find_element_by_name('foo') """ return self.find_element(by=By.NAME, value=name) def find_elements_by_name(self, name): """ Finds elements by name. :Args: - name: The name of the elements to find. :Returns: - list of webelement - a list with elements if any was found. an empty list if not :Usage: elements = driver.find_elements_by_name('foo') """ return self.find_elements(by=By.NAME, value=name) def find_element_by_tag_name(self, name): """ Finds an element by tag name. :Args: - name - name of html tag (eg: h1, a, span) :Returns: - WebElement - the element if it was found :Raises: - NoSuchElementException - if the element wasn't found :Usage: element = driver.find_element_by_tag_name('h1') """ return self.find_element(by=By.TAG_NAME, value=name) def find_elements_by_tag_name(self, name): """ Finds elements by tag name. :Args: - name - name of html tag (eg: h1, a, span) :Returns: - list of WebElement - a list with elements if any was found. An empty list if not :Usage: elements = driver.find_elements_by_tag_name('h1') """ return self.find_elements(by=By.TAG_NAME, value=name) def find_element_by_class_name(self, name): """ Finds an element by class name. :Args: - name: The class name of the element to find. :Returns: - WebElement - the element if it was found :Raises: - NoSuchElementException - if the element wasn't found :Usage: element = driver.find_element_by_class_name('foo') """ return self.find_element(by=By.CLASS_NAME, value=name) def find_elements_by_class_name(self, name): """ Finds elements by class name. :Args: - name: The class name of the elements to find. :Returns: - list of WebElement - a list with elements if any was found. An empty list if not :Usage: elements = driver.find_elements_by_class_name('foo') """ return self.find_elements(by=By.CLASS_NAME, value=name) def find_element_by_css_selector(self, css_selector): """ Finds an element by css selector. :Args: - css_selector - CSS selector string, ex: 'a.nav#home' :Returns: - WebElement - the element if it was found :Raises: - NoSuchElementException - if the element wasn't found :Usage: element = driver.find_element_by_css_selector('#foo') """ return self.find_element(by=By.CSS_SELECTOR, value=css_selector) def find_elements_by_css_selector(self, css_selector): """ Finds elements by css selector. :Args: - css_selector - CSS selector string, ex: 'a.nav#home' :Returns: - list of WebElement - a list with elements if any was found. An empty list if not :Usage: elements = driver.find_elements_by_css_selector('.foo') """ return self.find_elements(by=By.CSS_SELECTOR, value=css_selector)def find_element(self, by=By.ID, value=None): """ Find an element given a By strategy and locator. Prefer the find_element_by_* methods when possible. :Usage: element = driver.find_element(By.ID, 'foo') :rtype: WebElement """ if self.w3c: if by == By.ID: by = By.CSS_SELECTOR value = '[id="%s"]' % value elif by == By.TAG_NAME: by = By.CSS_SELECTOR elif by == By.CLASS_NAME: by = By.CSS_SELECTOR value = ".%s" % value elif by == By.NAME: by = By.CSS_SELECTOR value = '[name="%s"]' % value return self.execute(Command.FIND_ELEMENT, { 'using': by, 'value': value})['value'] def find_elements(self, by=By.ID, value=None): """ Find elements given a By strategy and locator. Prefer the find_elements_by_* methods when possible. :Usage: elements = driver.find_elements(By.CLASS_NAME, 'foo') :rtype: list of WebElement """ if self.w3c: if by == By.ID: by = By.CSS_SELECTOR value = '[id="%s"]' % value elif by == By.TAG_NAME: by = By.CSS_SELECTOR elif by == By.CLASS_NAME: by = By.CSS_SELECTOR value = ".%s" % value elif by == By.NAME: by = By.CSS_SELECTOR value = '[name="%s"]' % value # Return empty list if driver returns null # See https://github.com/SeleniumHQ/selenium/issues/4555 return self.execute(Command.FIND_ELEMENTS, { 'using': by, 'value': value})['value'] or []从以上实现的方法中，execute 方法实现在这里不在赘述实现，上一节已有说明，本节主要介绍方法使用。
首先查看 find_element_by_id 方法的使用，在方法说明中已经介绍使用方法：
element = driver.find_element_by_id('foo')该方法注释说明为（以下为了清晰说明，使用截图展示注释）：
通过注释说明得知，find_element_by_id 方法找到id为指定值的元素，并返回这个元素。
查看具体实现为：
self.find_element(by=By.ID, value=id_)以上实现调用了 find_element 方法，并且传入 by的值为By.ID，随后传入具体值；首先查看By类（selenium.webdriver.common.by）：
class By(object): """ Set of supported locator strategies. """ ID = "id" XPATH = "xpath" LINK_TEXT = "link text" PARTIAL_LINK_TEXT = "partial link text" NAME = "name" TAG_NAME = "tag name" CLASS_NAME = "class name" CSS_SELECTOR = "css selector"这个类与Command（selenium.webdriver.remote.command）类作用类似，上节已说明Command在这里也不过多说明By。
在这里查看 find_element 方法实现：
def find_element(self, =By.ID, value=None): """ Find an element given a By strategy and locator. Prefer the find_element_by_* methods when possible. :Usage: element = driver.find_element(By.ID, 'foo') :rtype: WebElement """ if self.w3c: if by == By.ID: by = By.CSS_SELECTOR value = '[id="%s"]' % value elif by == By.TAG_NAME: by = By.CSS_SELECTOR elif by == By.CLASS_NAME: by = By.CSS_SELECTOR value = ".%s" % value elif by == By.NAME: by = By.CSS_SEhj0ECTOR value = '[name="%s"]' % value return self.execute(Command.FIND_ELEMENT, { 'using': by, 'value': value})['value']以上类首先判断查找类型，随后进行值的拼接，最后把查找方式和值传入 execute 方法中，随后返回元素对象。
几乎所有的元素查找方法，实现相同，我们简单实用这个函数。
写代码前，我们需要打开百度网址，审查元素查找id值：
得到输入框的id值为kw，那么代码应该如下：
from selenium import webdriverdriver = webdriver.Chrome()driver.get("https://www.baidu.com/")input = driver.find_element_by_id('kw')# print('作者博客：https://blog.csdn.net/A757291228')#支持原创，转载请贴上链接由于查到到元素后返回的是元素对象：
在元素类（selenium.webdriver.remote.webelement）中查找方法，找到如下方法：
def send_keys(self, *value): """Simulates typing into the element. :Args: - value - A string for typing, or setting form fields. For setting file inputs, this could be a local file path. Use this to send simple key events or to fill out form fields:: form_textfield = driver.find_element_by_name('username') form_textfield.send_keys("admin") This can also be used to set file inputs. :: file_input = driver.find_element_by_name('profilePic') file_input.send_keys("path/to/profilepic.gif") # Generally it's better to wrap the file path in one of the methods # in os.path to return the actual path to support cross OS testing. # file_input.send_keys(os.path.abspath("path/to/profilepic.gif")) """ # transfer file to another machine only if remote driver is used # the same behaviour as for java binding if self.parent._is_remote: local_file = self.parent.file_detector.is_local_file(*value) if local_file is not None: value = self._upload(local_file) self._execute(Command.SEND_KEYS_TO_ELEMENT, {'text': "".join(keys_to_typing(value)), 'value': keys_to_typing(value)})# Private Methods def _execute(self, command, params=None): """Executes a command against the underlying HTML element. Args: command: The name of the command to _execute as a string. params: A dictionary of named parameters to send with the command. Returns: The command's JSON response loaded into a dictionary object. """ if not params: params = {} params['id'] = self._id return self._parent.execute(command, params)得知 send_keys 也是通过 execute 发送命令得到结果。在注释说明中得到了 send_keys 的使用方法为：
form_textfield.send_keys("admin")我们修改之前的代码：
from selenium import webdriverdriver = webdriver.Chrome()driver.get("https://www.baidu.com/")input = driver.find_element_by_id('kw')input.send_keys("CSDN A757291228")# print('作者博客：https://blog.csdn.net/A757291228')#支持原创，转载请贴上链接最后还查个点击即可完成自动化搜索功能；我们继续查看元素类，找到如下方法：
def click(self): """Clicks the element.""" self._execute(Command.CLICK_ELEMENT)click 方法与 send_keys 方法实现相同，不在赘述。直接使用click方法即可进行元素的点击。查找百度搜索点击按钮的id：
修改代码如下：
from selenium import webdriverdriver = webdriver.Chrome()driver.get("https://www.baidu.com/")input = driver.find_element_by_id('kw')input.send_keys("CSDN A757291228")enter = driver.find_element_by_id('su')enter.click()# print('作者博客：https://blog.csdn.net/A757291228')#支持原创，转载请贴上链接运行结果如下：
总结
我们简单的学习了使用 selenium 打开浏览器搜索 了“CSDN A757191228” ，在这个简单的例子的学习中，学习到的不仅是这个例子原本的那几行代码；通过实现分析，了解了其它功能函数所在的位置，可以通过这些功能函数，实现自己想要的功能！
从框架实现上分析可以事半功倍的学习框架的使用，以及了解框架的实现原理，更加利于我们的开发使用。