ww
definition
A browser is software that is used to access the internet. A browser lets you visit websites and do activities within them like login, view multimedia, link from one site to another,visit one page from another,print,send and receive email,among many other activities
a thing made or adapted for a particular purpose, especially a piece of mechanical or electronic equipment.
a hypertext document connected to the World Wide Web.
abbreviated WWW or the Web is an information space where documents and other web resources are identified by Uniform Resource Locators URLs, interlinked by hypertext links, and accessible via the Internet. English scientist Tim Berners-Lee invented the World Wide Web in 1989
JavaScript can change HTML attribute values.
In this case JavaScript changes the value of the src (source) attribute of an image.