check the console section of inspect element
we place elements in the head of your HTML to have them executed before the page loads if you place it in the body then it loads with the webpage
javascript is used for webpages
javascript differs form c and c++ in the fact that javascript is dynamic typed which allows variables to change during runtime
the main difference between var and let is that var is defined globally while let is defined locally
java applet was a language that was used for webpages but stoped being used becuase of the relience on plugins security reasons and preformace issues
object element are used provide a way to embed multimedia or other types of content in a web page while offering fallback content for browsers that do not support the embedded resource.
An expression is any valid set of literals, variables, operators, and expressions that evaluates to a single value.
You cant mess with the DOM until the page has fully loaded.