JavaScript Questions & Answers – Web Sockets

This set of Javascript Multiple Choice Questions & Answers (MCQs) focuses on “Web Sockets”.

1. Which of the following is a stateless protocol?
a) HTML
b) XHTML
c) HTTP
d) XML
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2. What does the value 2 of the WebSocket attribute Socket.readyState indicate?
a) Closed connection
b) Handshake connection
c) Unestablished connection
d) Established connection and communication is possible
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3. How many WebSocket events are available?
a) 2
b) 3
c) 4
d) 5
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4. Which method is used to close the WebSocket?
a) Socket.flush()
b) Socket.close()
c) Socket.Close()
d) Socket.dispose()
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5. How does the client and the server communicate following the rules defined by the WebSocket protocol?
a) Long-lived TCP Socket
b) Short-lived TCP Socket
c) UDP Socket
d) HTTP Socket
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6. Which of the following is not a socket property?
a) onopen
b) readyState
c) onmessage
d) ready
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7. What does the following JavaScript code snippet do?

var httpserver = new http.Server();

a) Create an HTTP Server
b) Create HTTP Connection between Client and Server
c) HTTP Server & Connection
d) Create a connection between two servers
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8. How can we check the subprotocol being used by the client?
a) subprotocol property
b) protocol property
c) clientprotocol property
d) client property
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9. How will you transmit data using the connection?
a) send(data)
b) Socket.send(“data”)
c) Socket.send(data)
d) Socket(data)
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10. Which of the following is not a WebSocket event?
a) open
b) close
c) error
d) deny
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11. What will be the output of the following JavaScript code?

<p id="demo"></p>
<script>
function myFunction() 
{
   var str = "hello to \r world."; 
   var patt1 = /\v/;
   var result = str.search(patt1);
   document.getElementById("demo").innerHTML = result;
}
</script>

a) 8
b) 9
c) 3
d) -1
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12. What will be the output of the following JavaScript code?

<p id="demo"></p>
<script>
function myFunction() 
{
   var str = "Hello World!"; 
   var patt1 = /\127/g;
   var result = str.match(patt1);
   if(result) 
  	result=true;
   else
  	result=false;
   document.getElementById("demo").innerHTML = result;
}
</script>

a) true
b) false
c) error
d) null
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13. What will be the output of the following JavaScript code?

<p id="demo"></p>
<script>
function myFunction() 
{
   var str = "Hello World!"; 
   var patt1 = /\x57/g;
   var result = str.match(patt1);
   if(result) 
  	result=true;
   else
  	result=false;
 
   document.getElementById("demo").innerHTML = result;
}
</script>

a) error
b) false
c) true
d) undefined
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14. What will be the output of the following JavaScript code?

<p id="demo"></p>
<script>
function myFunction() 
{
   var str = "Visit W3Schools. Hello World!"; 
   var patt1 = /\u0057/g;
   var result = str.match(patt1);
   var result = str.match(patt1);
   if(result) 
  	result=true;
   else
  	result=false;
   document.getElementById("demo").innerHTML = result;
}
</script>

a) true
b) false
c) error
d) undefined
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15. What will be the output of the following JavaScript code?

<p id="demo"></p>
<script>
function myFunction() 
{
   var str = "100%!";
   var patt1 = /\W/g;
   var result = str.match(patt1);
   var result = str.match(patt1);
   if(result) 
  	result=true;
   else
  	result=false;
   document.getElementById("demo").innerHTML = result;
}
</script>

a) false
b) true
c) error
d) undefined
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Sanfoundry Global Education & Learning Series – Javascript Programming.