Sockets — Part 1 MCQs with Explanations

HTTP is a stateless protocol. A stateless protocol does not require the server to retain information or status about each user for the duration of multiple requests.

The readonly attribute readyState represents the state of the connection. It can have the following values: 1. A value of 0 indicates that the connection has not yet been established. 2. A value of 1 indicates that the connection is established and communication is possible. 3. A value of 2 indicates that the connection is going through the closing handshake. 4. A value of 3 indicates that the connection has been closed or could not be opened.

There are fourWebSocket events namely : 1. open 2. close 3. message 4. error

The Socket.close() is used to close the WebSocket.

The client and server communicate over a long-lived TCP socket following rules defined by the WebSocket protocol.

There is no Socket property called ready.

Once the connection is established, the client can determine which subprotocol is in use by checking the protocol property of the socket.

The Socket.send(data) method transmits data using the connection.

There is no WebSocket event named deny. The four WebSocket events are 1. open 2. close 3. essage 4. error

The history object contains the URLs visited by the user (within a browser window).

The history object belongs to the Window object.

There are three methods belongign to the History object namely : 1. back() 2. forward() 3. go()

The forward() method loads the next URL in the history list.

The property location.hash needs to be updated to display the updated URL in the location bar.

The pushState() method adds a particular state to the browsing history.

When a web app enters a new state, it calls history.pushState() to add that state to the browsing history.

The replaceState() method is used to replace the current history state instead of adding a new state to the browsing history.

window.history.replaceState(stateObj, title, url) : This is just like window.history.pushState, except that the current browser state is removed from the history, so you cannot hit “back” to return to it.

The window.onpopstate event is fired whenever a state object is removed from the browser history, which occurs on browser “back” or “forward”. State objects are persisted on the user’s hard disk between sessions, which is a nice feature. The object passed into a call to pushState or replaceState is provided as the state property on the event object in the “popstate” event.

R is an extension of and successor to the S language, which was itself a statistical language created in 1976 by John Chambers while at Bell Labs.

Both R and S are statistical languages.

R is an extension of and successor to the S language, which was itself a statistical language.

Generally, R can be used to suck in data, parse it, process it, and then visualize it for reporting purposes.

A glue language is generally used to collect the data, that is written out as a comma-separated file, and read it into R.

Within R, processing the data, splitting it, averaging it, aggregating it, overlaying two or more data sets, and then from with R, a chart that depicts the data out is done.

From R, the chart is imported into the Adobe Illustrator, or any other such program, where it can clean up things like font consistency and make sure axis labels with long names are visible.

A glue language is generally used to collect and format the data.

The Adobe Illustrator is used along with R to tighten and format the chart.

The R language is generally used to collect data that has been collected by the glue language and then ingest and process and chart.

All kinds of data can be run in R.

As a language, R is small, self-contained, extensible, and just fun to use.

Instead of a compiled installer, Linux users get the command sequence to install for their particular Linux flavor.

The PC installer comes in three flavors: Base is the base install, Contrib comes with compiled third-party packages, and Rtools comes with tools to build your own R packages.

The PC installer comes in three flavors: Base is the base install, Contrib comes with compiled third-party packages, and Rtools comes with tools to build your own R packages.

The PC installer comes in three flavors: Base is the base install, Contrib comes with compiled third-party packages, and Rtools comes with tools to build your own R packages.

The code of the R language has an extension .R.

The R Console is a command-line environment for running ad hoc R commands.

At any time, you can type ?(keyword) to open the help window for a particular subject.

For a more extensive search, just type ?? (keyword).

?? (keyword) is generally used for a more extensive search when compared to the keyword ?.