How to use preceding-sibling and following-sibling in xpath to find sibling nodes

How to use preceding-sibling and following-sibling in xpath to find sibling nodes

How to get all the preceding siblings of Apple

Xpath: "//ul/li[contains(text(),'Apple Mobiles')]/preceding-sibling::li"

This will give "Samsung Mobiles"

How to get all the following  siblings of Apple
Xpath: "//ul/li[contains(text(),'Apple Mobiles')]/following-sibling::li"

This will give all the preceding siblings ( Nokia Mobiles, HTC Mobiles, Sony Mobiles, Micromax mobiles)

There is trick to use preceding-sibling and following-sibling. Place matters when you use this at beginning it will give you reverse result
When you use preceding-sibling at beginning then it will give result  ( Nokia Mobiles, HTC Mobiles, Sony Mobiles, Micromax mobiles) instead of Samsung mobiles.

Xpath : "//li[preceding-sibling::li='Apple Mobiles']"

This will give Samsung mobiles.
when you use following-sibling at the beginning then it will give reverse result. Instead of giving all below nodes of Apple mobile this will give Samsung Mobiles.
Xpath: "//li[following-sibling::li='Apple Mobiles']"
Now the question is how to get all the nodes between Apple Mobiles and Sony Mobiles.

Xpath : "//ul/li[preceding-sibling::li='Apple Mobiles' and following-sibling::li='Sony Mobiles']"
This will return Nokia Mobiles and HTC Mobiles.

or
Xpath : "//ul/li[preceding-sibling::li[.='Apple Mobiles'] and following-sibling::li[.='Sony Mobiles']]"
Or You can use this in contains as well
Xpath: "//ul/li[preceding-sibling::li[contains(text(),'Apple Mobiles')] and following-sibling::li[contains(text(),'Sony Mobiles')]]"

How to find a sibling of a node

How to find a sibling of a node

There are many situation when we get difficulties to find the elements which do not have identification/attribute but their immediate siblings has some identification.

In above example if we want to get the text of H1 we can not use //h1 because there are more than one h1 on the page. If you see a and h1 both are siblings and children of div//[@class='title pad_btm15']
By using a sibling element's property we can find out his sibling. In above example we know id of a which is "mainContent" then we can get its sibling

Xpath:

"//a[@id='mainContent']/following-sibling::h1"


If you have more siblings with no attribute or no unique attribute like below.

then we can use the position us find out exact element using xpath:
Xpath:
Samsung Android Mobile
"//a[@id='mainContent']/following-sibling::h1[1]"

Nokia Android Mobile :
"//a[@id='mainContent']/following-sibling::h1[2]"

Which is the best way to locate an element?

We choose the method based on which gives the element in fastest way in all the browsers. Finding elements by ID is usually going to be the fastest option, because at its root, it eventually calls down to document.getElementById(), which is optimized by many browsers.
Finding elements by XPath is useful for finding elements using very complex selectors, and is the most flexible selection strategy, but it has the potential to be very slow, particularly in IE. In IE 6, 7, or 8, finding by XPath can be an order of magnitude slower than doing the same in Firefox. IE provides no native XPath-over-HTML solution, so the project must use a JavaScript XPath implementation, and the JavaScript engine in legacy versions of IE really is that much slower.
If you have a need to find an element using a complex selector, I usually recommend using CSS Selectors, if possible. It's not quite as flexible as XPath, but will cover many of the same cases, without exhibiting the extreme performance penalty on IE that XPath can.

How to use / and // in xpath

How to use / and // in xpath

Difference between / and //  

/

When / is used at the beginning of a path:

/div
it will define an absolute path to node "a" relative to the root. In this case, it will only find "a" nodes at the root of the XML tree.

//

When // is used at the beginning of a path:

//div

It will define a path to node "div" anywhere within the XML document. In this case, it will find "div" nodes located at any depth within the XML tree.

These XPath expressions can also be used in the middle of an XPath value to define ancestor-descendant relationships. When / is used in the middle of a path:

/div/a

Tt will define a path to node "a" that is a direct descendant (ie. a child) of node "div".

When // used in the middle of a path:

/div//a

It will define a path to node "a" that is any descendant (child node)  of node "div".

When we don't know the immediate parent of a child then we can use "." dot

will still find any node, "div", located anywhere within the XML tree. But, the XPath:

.//div

will find any node, "div", that is a descendant of the node . " In other words, preceding the "//" expression with a "." tells the XML search engine to execute the search relative to the current node reference.

Difference between Selenium RC and Selenium Web Driver

Selenium RC	Selenium Web driver
It is easy and small API. These API’s are less Object oriented	As compared to RC, it is bit complex and large API. API’s are entirely Object oriented
Selenium RC is slower since it uses a JavaScript program called Selenium Core. This Selenium Core is the one that directly controls the browser, not you.	Web Driver is faster than Selenium RC since it speaks directly to the browser uses the browser’s own engine to control it.
Selenium Core, just like other JavaScript codes, can access disabled elements.	Web Driver interacts with page elements in a more realistic way. It interacts natively with browser application
Required to start server before executing the test script.	Doesn’t required to start server before executing the test script.
It is standalone java program which allow you to run Html test suites.	It actual core API which has binding in a range of languages.
Selenium RC cannot support the headless HtmlUnit browser. It needs a real, visible browser to operate on.	Web Driver can support the headless HtmlUnit browser.
It doesn’t supports of moving mouse cursors.	It supports of moving mouse cursors.
Selenium RC Has Built-In Test Result Generator. Selenium RC automatically generates an HTML file of test results.	Web Driver has no built-in command that automatically generates a Test Results File.
It does not supports listeners	It supports the implementation of listeners
Selenium RC needs the help of the RC Server in order to do so.	web Driver directly talks to the browser
It does not support to test iphone/Android applications	It support to test iphone/Android applications
Selenium RC can support new browsers	It cannot readily support new browsers