Reflected Cross Site Scripting
Cross Site Scripting (XSS) attacks are a type of injection attack, where scripts are injected into a tusted website application. There are sub categories of XSS attack, which work very differently. Generally, an XSS attack is performed using a browser side script, with the intent to run on a different users session.
The intent of an XSS attack is to steal cookies, session tokens, or other sensitive information and divert this information to somewhere not intended. More information can be found on the OWASP website: https://www.owasp.org/index.php/Cross-site_Scripting_(XSS)