cheatsheets/xpath.md

title	layout
Xpath	default

CSS equivalents

CSS	Xpath
div p	//div//p
ul > li	//ul/li
div > *	//div/*
h1 ~ ul	//h1/following-sibling::ul
h1 ~ #id	//h1/following-sibling::[@id="id"]
---	---
:root	/
:root > body	/body
---	---
input[type="submit"]	//input[@type="submit"]
a[href^='/']	//a[starts-with(@href, '/')]
a[href$='pdf']	//a[ends-with(@href, '.pdf')]
---	---
#id	//[@id="id"]
.class	//[@class="class"] ...see below
---	---
ul > li:first-child	//ul/li[1]
ul > li:nth-child(2)	//ul/li[2]
ul > li:last-child	//ul/li[last()]
---	---
li#id:first-child	//li[@id="id"][1]
---	---
a:first-child	//a[1]
a:last-child	//a[last()]
li:first-of-type	//li[not(preceding-sibling::li)]
{:.greycode.no-head}

Class check

Xpath doesn't have the "check if part of space-separated list" operator, so this is the workaround:

//div[contains(concat(' ',normalize-space(@class),' '),' foobar ')]

jQuery equivalents

For things that CSS alone can't do.

jQuery	Xpath
$('ul > li').parent()	//ul/li/..
$('li').closest('section')	//li/ancestor-or-self::section
$('a').attr('href')	//a/@href
$('span').text()	//span/text()
{:.greycode.no-head}

Expressions

Prefixes

Begin your expression with any of these.

Prefix	Example
// anywhere	//hr[@class='edge']
./ relative	./a
/ root	/html/body/div
{:.greycode.no-head}

Axes

Separate your steps with /. Use two (//) if you don't want direct descendants.

Axis	Example
/ child	//ul/li/a
// descendant	//[@id="list"]//a
{:.greycode.no-head}

Selecting node data

//a                     #=> <a>
//a/text()              #=> "Go home"
//a/@href               #=> "index.html"
//a/*                   #=> All a's child elements

Predicates

Predicates ([])

Restricts a nodeset only if some condition is true. They can be chained.

//div[true()] 
//div[@class="head"]
//div[@class="head"][@id="top"]

Operators

Use operators to make conditionals.

# Comparison
  //a[@id = "xyz"]
  //a[@id != "xyz"]
  //a[@price > 25]

# Logic (and/or)
  //div[@id="head" and position()=2]
  //div[(x and y) or not(z)]

Using nodes

You can use nodes inside predicates.

# Use them inside functions
  //ul[count(li) > 2]
  //ul[count(li[@class='hide']) > 0]

# This returns `<ul>` that has a `<li>` child
  //ul[li]

Nesting predicates

This returns <section> if it has an <h1> descendant with id='hi'.

//section[//h1[@id='hi']]

Predicate order

Order is significant, these two are different.

a[1][@href='/']
a[@href='/'][1]

Indexing

Use [] with a number, or last() or position().

//a[1]                  # first <a>
//a[last()]             # last <a>
//ol/li[2]              # second <li>
//ol/li[position()=2]   # ...same as above

Functions

Node functions

text()                     # button[text()="Submit"]
name()                     # *[name()='div']
lang(str)
namespace-uri()

count()                    # table[count(tr)=1]
position()                 # ol/li[position()=2]

Boolean functions

not(expr)                  # button[not(text()="Submit")]

String functions

contains()                 # font[contains(@class,"head")]
starts-with()              # font[starts-with(@class,"head")]
ends-with()                # font[ends-with(@class,"head")]

concat(x,y)
substring(str, start, len)
substring-before("01/02", "/")  #=> 01
substring-after("01/02", "/")   #=> 02
translate()
normalize-space()
string-length()

Type conversion

string()
number()
boolean()

Axes

//ul/li
//div/h1/span

{:.light}

Descendant-or-self axis

When you use // for descendants, this is short or /descendant-or-self::.

//div//h4
//div/descendant-or-self::h4

//ul//[last()]
//ul/descendant-or-self::[last()]

Child axis

When no axis is specifid, a step with a name is short for child::name. This is what makes //a/b/c work.

//ul/li/a
//ul/child::li/child::a

Attribute axis

When you use @ for attributes, that's short for the attribute:: axis.

//a/@href
//a/attribute::href

//div[@id="box"]
//div[attribute::id="box"]

Other axes

There are other axes you can use.

Axis	Abbrev	Description
ancestor
ancestor-or-self
---	---	---
attribute	@	@href is short for attribute::href
child		div is short for child::div
descendant
descendant-or-self	//	// is short for /descendant-or-self::node()/
namespace
---	---	---
self	.	. is short for self::node()
parent	..	.. is short for parent::node()
---	---	---
following
following-sibling
preceding
preceding-sibling
{:.greycode}

More examples

//*                 # all elements
count(//*)          # count all elements
//h1[1]/text()      # hext of the first h1 heading
//li[span]          # Find a <li> with an <span> inside it
                    # ...expands to //li[child::span]
//ul/li/..          # use .. to select a parent

# Find a <section> that directly contains h1#section-name
  //section[child::h1[@id='section-name']]

# like jQuery's $().closest('.box')
  ./ancestor-or-self::[@class="box"]

# Find a <section> that contains h1#section-name
# (Same as above, but use descendant-or-self instead of child)
  //section[//*[@id='section-name']]

# Find <item> and check its attributes
  //item[@price > 2*@discount]

References

• Xpath test bed (whitebeam.org)