Introduction Simple programming language in the browser (Totally Client Side)Basically no relation to Java – just a marketing nameUsed to be incompatible versionsLater became a standard under ECMAWorks best in IE 5 or later, Netscape 6 or later, Mozilla 1.0 or later, including Firefox. Mozillaprobably has the best JavaScript implementation.We will not worry about weird JavaScript required by old browsers JavaScript Niche Make the client more responsive in a client/server systemA slightly “thicker” client, but better user experienceAdvantages: more responsive, doesn't require a request/response roundtrip e.g. on product detail page for a t-shirt, have a pop-up menu for color. Use JavaScript toswap the image to show different shirts without doing a whole form submit. JavaScript can do things in the browser: adjust the HTML in the page, adjust the window, opennew windowsJavascript cannot: use the local filesystem, do networking.