How to handle javascript alerts, confirmation and prompts

// Get a handle to the open alert, prompt or confirmation
Alert alert = driver.switchTo().alert();

Alert is an interface. There below are the methods that are used

//Will Click on OK button.
alert.accept();

// Will click on Cancel button.
alert.dismiss()

//will get the text which is present on th Alert.
alert.getText();

//Will pass the text to the prompt popup
alert.sendkeys();