1.xPath Profile
XPath is a find information in XML and HTML documents in languages that can be used to traverse the elements and attributes in XML and HTML documents
XPath installation
Chrome plug-in XPath Helper
Upper right corner of the browser spot Chrome: extensions more tools ----- ----- Google store -------- Check XPath Helper (need over the wall)
2. Detailed grammar
Xpath node type:
Element, attribute, text, namespace, processing instructions, comments and documents
Xpath: the path expressions to select nodes or node location of the XML document
Methods: First, find the directory element is the "precise elements" property that is the only way to identify, locate, locate this attribute is used;
1. By positioning the element itself unique properties
Methods: where to find the target element "precise elements" that uniquely identifies the property, use this property to target
- By id attribute positioning 1.1
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Example: find_element_by_xpath ( " // INPUT [@ ID = 'INPUT'] " ) # @ followed by the property may be any property
- 1.2 positioned by the name attribute
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例：find_element_by_xpath("//div[@name='q']")
2. With a unique directory attribute positioning
Methods: The target is not the only element attribute, to find the target element similar to the parent directory "unique element" as a starting position, and based on this relative position of the layer by layer to write to the target location subdirectory
Example:
find_element_by_xpath("//span[@id='input-container']/input") find_element_by_xpath("//div[@id='hd']/form/span/input") find_element_by_xpath("//div[@name='q']/form/span/input")
3. xpath do Boolean
find_element_by_xpath ( " // div [@ id = 'hd' or @ name = 'q'] " ) # Find id or name is q is the hd
4. The dual filter conditions are
find_element_by_xpath("//div[@id='hd'][@name='q'")
5. The existence of hierarchical relationships catalog elements
Example 1:
find_element_by_xpath("//ul[@class='app-list']/li[contains(@class,'safe')]/div")
Example 2: re-positioning of one element targets (repositioning positioning dl dt)
find_element_by_xpath("//form[@id='J_login_form]/dl/dt/input[@id='J_password']")
6. fuzzy positioning
6.1 contains methods (included)
find_element_by_xpath ( " // A [the contains (@ name, 'trnews')] " ) # method for obtaining the element is trnews
6.2 start-with method (beginning with XX)
find_element_by_xpath ( " // A [Start-with (@ the href, 'http')] " ) # Select element beginning with http
6.3 text method
find_element_by_xpath ( " // A [the contains (text (), 'news')] " ) to find the hyperlink text content elements
find_element_by_xpath ( " // * [text () = 'news'] " ) Find all content elements of the word quit
7, xpath contains some logic Usage
// * [count (XXX) = 2] // count the number of elements = XXX node 2 // * [local-name () = ' xxx ' ] // find the tag element is xxx // * [starts- with (local-name (), ' x ' )] // find all the elements at the beginning of the tag to x // * [the contains (local-name (), ' x ' )] // find all tag contained element x / / * [string-length (local -name ()) = 3] // find all the tag element length is 3 // xxx | // yyy // plurality Pathfinder