A web browser is a code interpreter that takes HTML and script code to present a document to the user in an attractive and useful format, including text, images, and video clips. It allows the user to interact with dynamic elements including search fields, hyperlinks, forms, video and audio controls, and many others.
There are many ways for an application to manage this dynamic interaction with users. The one way that is most common in today's web applications is the use of client-side script code. This means that the server sends code to the client that will be executed by the web browser.
When user input is used to determine the script code behavior, and this input is not properly validated and sanitized in order to prevent it from containing code, rather than information, the injected code will be executed...
