Web Science/Part1: Foundations of the web/Dynamic Web Content/Ajax and the XMLHttpRequest class/quiz

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<quiz display=simple> {What is true about using JavaScript for issuing an HTTP request from some webpage?} + Usually only HTTP requests to the domain from which the webpage that contains the calling JavaScript was downloaded are possible - It is possible to make HTTP requests to other servers if they run on port 433 + It is possible to make HTTP requests to other servers if they have a cross origin resource sharing policy + It is possible if the from which the webpage that contains the calling JavaScript was downloaded is white listed in the Access-Origin Header field of the server response. - If not allowed the browser will prevent JavaScript from making the HTTP request. |interestingly the request is made and only the response is dropped (this makes sense otherwise the Access-Control header of the response could not be processed by the browser SEND MAIL TO CHRISTOPH) - the repsonse has to be in JSON (JavaScript object notation) | No, the response can be in any format.

{Why is JavaScript usefull for the World Wide Web?} + It enables more interactive websites | even though HTML allows for input fields and text areas JavaScript increases the amount of interactivity + It can take loads of traffic from the web server or the web server's backend | yes for example if data needs to be sorted this can easily be done by the client - It can help websites to better communicate with search engines and provide metadata like RDFa | No indeed search engines frequently ignore JavaScript - Without JavaScript, the structure of web content could not be completely seperated from layout and formatting | JavaScript does not aim to support people to separate structure from layout and formatting + It can help to easily make asynchronous HTTP requests to a web server | This is useful since a webpage does not have to be assembled at the server which blocks but can rather be asynchronously assembled on the client side.

{What are the advantages of JavaScript libraries?} + They provide an API that will work on almost any browser | The most popular browsers and many different versions are supported by these libraries. - They make JavaScript more powerful | No, they don't change the expressiveness of JavaScript at all

{Which of the following are JavaScript libraries} + jQuery - PHP - Java + mootools + Prototype - Netscape

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