Question

Javascript Questions:

1. Which of the following is not a way to avoid adding objects to
the global namespace?

a. Create and assign variables and event handlers within an IIFE.
b. Use the var keyword.
c. Use an object literal as a namespace.
d. Create and attach an event handler function within the event
   onload handler.

2. Data properties added by assignment are writable, configurable, and
enumerable by default. Data properties added with the defineProperty
method are

a. writable, configurable, and enumerable by default.
b. non-writable, non-configurable, and non-enumerable by default.
c. writable, non-configurable, and non-enumerable by default.
d. writable, configurable, and non-enumerable by default.

3. Which of the following is a benefit of using the JSON data format?

a. It's the only data format that works with JavaScript.
b. It's a subset of XML so you can use existing XML objects
   to work with it.
c. It's a subset of JavaScript so you can use familiar JavaScript
   syntax to work with it.
d. It's a subset of HTML so you can use the DOM to work with it.

4. The six data types allowed in JSON are strings, numbers, Booleans,
arrays, objects, and

a. null
b. undefined
c. function definitions
d. integers

5. The global JSON object provides which two methods for converting
JavaScript objects to JSON strings and back again?

  a. stringify and replacer
b. stringify and reviver
c. stringify and parse
d. parse and replacer

6. A jQuery selector includes all but one of the following.
Which one is it?

a. $ sign
b. quotation marks
c. parentheses
d. dot operator

7. What does the following jQuery code do?

$("h2").prev();

a. Gets the h2 element that precedes the current element
b. Gets the element in the HTML that precedes the selected h2
   element
c. Gets the previous sibling of the selected h2 element
d. Gets the previous sibling of the selected h2 element that is an
   h2 element

8. Which of the following event methods occurs when the user moves the
mouse pointer over an element and then clicks on it?

a. click
b. mouseover
c. mouseout
d. click and mouseover

9. Before you use a plugin, you have to know all but one of the
following. Which one is it?

a. the HTML that it requires
b. how its CSS works
c. the methods that it provides
d. the options that it provides

10. To provide for implicit iteration, a plugin should use

a. a for loop
b. a while loop
c. an each method
d. the this keyword

Answer 1

Answer:

1. B- Use var keyword – it is used to create an object in javascript. How it can avoid adding using an object in namespace.
2. Data properties added with the defineProperty method are configurable, writable and non-enumerable by default. Option –d is the answer
3. It is a subset of JavaScript so you can use familiar JavaScript syntax to work with it. Option- c is answer.
4. The six data types allowed in JSON are strings, numbers, Booleans, arrays, objects, and null. Option –a is correct.
5. JSON.stringfy() convert js object to JSON string and JSON.parse() returns javascript. So option-c is correct.
6. A jquery selector includes $ sign, quotation marks, parentheses but not .dot operator. Option D is the answer
7. This jquery gets the previous sibling of the selected h2 element. Option c is answer.
8. Mouseover and click events should be, the first user moves the mouse over the object then click. Option-d is answer.
9. Before you use a plugin, you have to know the methods that it provides. Option c should be correct.
10. To provide implicit iteration, a plugin should use each method. Option c is correct.