Can you explain what a selector is in the Selenium testing automation tool?

In Selenium, a selector is a way to identify an element on a web page for interaction with it (for example, clicking, entering text).

Selectors can be different:

• By ID (By.id)
• By class name (By.className)
• By tag name (By.tagName)
• By CSS selector (By.cssSelector)
• By XPath (By.xpath)

For example, to find a button with id="submit":

WebElement button = driver.findElement(By.id("submit"));
button.click();

Choosing the right selector is important for test reliability — it should be unique and stable despite page changes.