enter JavaScript (1996-8)
Javascript engine – can run programs downloaded alongside the HTML, CSS and images.
JavaScript
programs can detect UI events (clicks, etc.) and run code when the user does something:
interactivity is programmable.
browser
JavaScript Engine
UI HTML / CSS
HTML / CSS
data
data
JavaScript
JavaScript
programs
programs
data
other
other
data (e.g.
data (e.g.
images)
images)
JavaScript programs, via the engine, can access and modify the HTML / CSS data, dynamically changing the UI that’s displayed.