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diff --git a/testing/marionette/client/docs/advanced/findelement.rst b/testing/marionette/client/docs/advanced/findelement.rst new file mode 100644 index 0000000000..6f61fa5e25 --- /dev/null +++ b/testing/marionette/client/docs/advanced/findelement.rst @@ -0,0 +1,87 @@ +Finding Elements +================ +.. py:currentmodule:: marionette_driver.marionette + +One of the most common and yet often most difficult tasks in Marionette is +finding a DOM element on a webpage or in the chrome UI. Marionette provides +several different search strategies to use when finding elements. All search +strategies work with both :func:`~Marionette.find_element` and +:func:`~Marionette.find_elements`, though some strategies are not implemented +in chrome scope. + +In the event that more than one element is matched by the query, +:func:`~Marionette.find_element` will only return the first element found. In +the event that no elements are matched by the query, +:func:`~Marionette.find_element` will raise `NoSuchElementException` while +:func:`~Marionette.find_elements` will return an empty list. + +Search Strategies +----------------- + +Search strategies are defined in the :class:`By` class:: + + from marionette_driver import By + print(By.ID) + +The strategies are: + +* `id` - The easiest way to find an element is to refer to its id directly:: + + container = client.find_element(By.ID, 'container') + +* `class name` - To find elements belonging to a certain class, use `class name`:: + + buttons = client.find_elements(By.CLASS_NAME, 'button') + +* `css selector` - It's also possible to find elements using a `css selector`_:: + + container_buttons = client.find_elements(By.CSS_SELECTOR, '#container .buttons') + +* `name` - Find elements by their name attribute (not implemented in chrome + scope):: + + form = client.find_element(By.NAME, 'signup') + +* `tag name` - To find all the elements with a given tag, use `tag name`:: + + paragraphs = client.find_elements(By.TAG_NAME, 'p') + +* `link text` - A convenience strategy for finding link elements by their + innerHTML (not implemented in chrome scope):: + + link = client.find_element(By.LINK_TEXT, 'Click me!') + +* `partial link text` - Same as `link text` except substrings of the innerHTML + are matched (not implemented in chrome scope):: + + link = client.find_element(By.PARTIAL_LINK_TEXT, 'Clic') + +* `xpath` - Find elements using an xpath_ query:: + + elem = client.find_element(By.XPATH, './/*[@id="foobar"') + +.. _css selector: https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Getting_Started/Selectors +.. _xpath: https://developer.mozilla.org/en-US/docs/Web/XPath + + + +Chaining Searches +----------------- + +In addition to the methods on the Marionette object, HTMLElement objects also +provide :func:`~HTMLElement.find_element` and :func:`~HTMLElement.find_elements` +methods. The difference is that only child nodes of the element will be searched. +Consider the following html snippet:: + + <div id="content"> + <span id="main"></span> + </div> + <div id="footer"></div> + +Doing the following will work:: + + client.find_element(By.ID, 'container').find_element(By.ID, 'main') + +But this will raise a `NoSuchElementException`:: + + client.find_element(By.ID, 'container').find_element(By.ID, 'footer') |