Locating UI elements by name/id/link text is certainly the most simplest way of locator identification. But not all HTML elements within a page are defined by an id or name. For such situations where the user is unable to locate using the id or name locator strategies we use the CSS locator strategy.
CSS (cascading style sheets) is a style sheet language used for describing the rendering of documents written in mark-up languages such as HTML and XML. The CSS locator strategy uses the CSS selectors for finding the UI elements. Selenium supports CSS 1.0, CSS 2.0 and CSS 3.0 selectors. Although compared to the name and id locator strategies CSS locators are more complex to form, they can be used to locate even the most complicated objects within an HTML document. Also CSS locators are much faster compared to xPath locators. Owing to these reasons majority of selenium users recommend CSS as the most appropriate locating strategy of their choice.
