What is the difference between cssSelector & Xpath and which is better with respect to performance for cross browser testing?

selenium selenium-webdriver xpath css-selectors webdriver
Chetan picture Chetan · May 28, 2013 · Viewed 109.3k times · Source

I am working with the Selenium WebDriver 2.25.0 on multilingual web application & mainly test the page content (For different languages like Arabic, English, Russian & so on).

For my application which is better according to performance & make sure that it should be support for all the browsers (i.e. IE 7,8,9, FF, Chrome etc).

Thanks in advance for your valueable suggestions.

Answer

nilesh picture nilesh · May 28, 2013

CSS selectors perform far better than Xpath and it is well documented in Selenium community. Here are some reasons,

  • Xpath engines are different in each browser, hence make them inconsistent
  • IE does not have a native xpath engine, therefore selenium injects its own xpath engine for compatibility of its API. Hence we lose the advantage of using native browser features that WebDriver inherently promotes.
  • Xpath tend to become complex and hence make hard to read in my opinion

However there are some situations where, you need to use xpath, for example, searching for a parent element or searching element by its text (I wouldn't recommend the later).

You can read blog from Simon here . He also recommends CSS over Xpath.

If you are testing content then do not use selectors that are dependent on the content of the elements. That will be a maintenance nightmare for every locale. Try talking with developers and use techniques that they used to externalize the text in the application, like dictionaries or resource bundles etc. Here is my blog that explains it in detail.

edit 1

Thanks to @parishodak, here is the link which provides the numbers proving that CSS performance is better

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