Selenium tricks for CSS and Xpath locators

            Selenium tricks for CSS and Xpath locators

In this post you will learn some CSS rules and how to use CSS selectors and Xpath locators in Selenium.

(1) Id:
An element's id is defined as "[@id='idName']" in Xpath but "#idName" in CSS.
For example, a 'div' element with id 'panel' will be represented as below:
In Xpath locator 

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1	//div[@id='panel']

In CSS selector

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1	css=div#panel

(2) Class:
An element's class is defined as "[@class='className']" in Xpath but ".className" in CSS.  
For example, a 'div' element with class 'panelClass' will be represented as below:
In Xpath locator 

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1	//div[@class='panelClass']

In CSS selector

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1	css=div.panelClass

For element with multiple class we need to separate with space(" ") in Xpath and dot(".") in case of CSS. See below example,
In Xpath locator 

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1	//div[@class='panelClass1 panelClass2']

In CSS selector

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1	css=div.panelClass1.panelClass2

(3) Any Attributes:
For selecting an element by its any of the attribute(say "name" is an attribute of a 'div' element and "type" in an "input" element) is given below: 
In Xpath locator 

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1	//div[@name='continue']

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1	//input[@type='button']

In CSS selector

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1	css=div[name='continue']

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1	css=input[type='button']

(4) Direct Child:
A direct child of an element is denoted as "/" in Xpath and ">" in CSS selector. See the example below for a direct child "li" for a "ul" element:
In Xpath locator 

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//ul/li

In CSS selector

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1	css=ul > li

(5) Child or Subchild:
A direct child of an element is denoted as "//" in Xpath and a wehite-space(" ") in CSS selector. See the example below for a child/subchild "li" for a "ul" element:
In Xpath locator 

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1

//ul//li

In CSS selector

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css=ul li

Note that "ul li" and "ul > li" are different. If you are confusing please go through this article.

(6) nth Child:
For finding 'nth' child, in Xpath we denote as "[n]" and in CSS we denote as ":nth-of-type(n)". See the below example,

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<ol id="drinks">   <li>Coffee</li>   <li>Tea</li>   <li>Milk</li>   <li>Soup</li>   <li>Soft Drinks</li> </ol>

In Xpath locator 

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1	//ul[@id='drinks']/li[5]

In CSS selector

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1	css=ul#drinks li:nth-of-type(5)

Also you can use ":nth-child" but the difference between ":nth-child" and ":nth-of-type(n)" is:
li:nth-child(2)
This means, select an element if It is a paragraph element and the second child of a parent.
li:nth-of-type(2)
This means, select the second paragraph child of a parent. This is less conditional.
See here for more details on difference between the above two.

If we want to select the "fifth li element" (Soft Drinks) in this list, we can use the nth-of-type, which will find the fifth li in the list.

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1	css=ul#drinks li:nth-of-type(5)

On the other hand, if we want to get the "fifth element" only if it is a li element, we can use a filtered nth-child which will select again (Soft Drinks) here.

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1	css=ul#drinks li:nth-child(5)

(7) Parent of an element:
Parent of an element can be represented as "/.." in Xpath and ":parent" in CSS selectors. For example, if you want to indicate parent of the list item of class 'blue'

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<ul>   <li class="blue">first</li>   <li>second</li>   <li>third</li>   <li>fourth</li>   <li>fifth</li> </ul>

In Xpath locator 

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1	//li[@class='blue']/..

In CSS selector

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1	css=li.blue:parent

(8) Next Sibling:
Next sibling is nothing but next adjacent element which is inside the same parent on the page. An adjacent sibling combinator selector allows you to select an element that is directly after another specific element. For example, If you want to select the sibling of "li" element with class "blue" which is 'second' list item, 
In Xpath locator 

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1	//li[@class='blue']/../li[2]

In CSS selector

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1	css=li.blue + li

Similarly, if you want to indicate 'third' list item, see the below
In Xpath locator 

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1	//li[@class='blue']/../li[3]

In CSS selector

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1	css=li.blue + li + li

(9) Match by Innertext:
There is a javascript methodcontains() which can be used to check the inner text of a web element. For example a link with text "Sign in"
In Xpath locator 

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1	//a[contains(text(),'Sign in')]

or 

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1	//a[contains(string(),'Sign in')]

In CSS selector

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1	css=a:contains('Sign in')

(10) Match by Sub-string:
This is interesting and is described below. With this we can match strings with its partial text. E.g. prefix, suffix or any pattern(sub-string)

(i) Match a Sub-string(pattern):
Taking an example of a 'div' with an 'id' that contains the text "pattern"

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<div id="someText_pattern_someOtherText"> ... </div>

In Xpath locator, we need to use "contains()" to match a sub-string

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1	//div[contains(@id,'pattern')]

In CSS selector, we need to use "*=" for matching a sub-string

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1	css=div[id*='pattern']

(ii) Match a prefix:
Taking an example of a 'div' with an 'id' that starts with the text "prefixString"

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<div id="prefixString_pattern_someOtherText"> ... </div>

In Xpath locator, we need to use "starts-with" to match a prefix

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1	//div[starts-with(@id,"prefixString")]

In CSS selector, we need to use "^=" for matching a prefix

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1	css=div[id^='prefixString']

(iii) Match a suffix:
Taking an example of a 'div' with an 'id' that starts with the text "suffixString"

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<div id="prefixString_pattern_sufixString"> ... </div>

In Xpath locator, we need to use "ends-with" to match a suffix Note that "ends-with()" is a standard XPath 2.0 function only, it won't work if you are using Xpath 1.0 engine 

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1	//div[ends-with(@id,"suffixString")]

In CSS selector, we need to use "$=" for matching a suffix

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1	css=div[id$='suffixString']

The summary of sub-string match is listed out in the following table:

	Match a Sub-string	Match a Prefix	Match a Suffix
Xpath	contains()	starts-with()	ends-with()
CSS	*=	^=	$=