Lesson 0

Question 1

What’s the code to print in the browser’s console?

Answer 1

console.log(“Hello world”);

Question 2

JavaScript variable syntax

Answer 2

- String
 \+ var firstName = "james";
 \+ Always put var first. Strings are inside "".
- Numbers
 \+ var age = 32;

Question 3

What is the replace method?

Answer 3

• The .replace() method returns a new string with some or all matches of a pattern replaced by a replacement. JavaScript
• Example:
  var email = “udacity.com”;
  var newEmail = email.replace(“udacity, “gmail”);

Question 4

What is the append method?

Answer 4

• The .append() method inserts the specified content as the last child of each element in the jQuery collection.
• Example:
  //Original html
  <h2>Greetings</h2><div>
  <div>Hello</div>
  <div>Goodbye</div>
  </div>

  //jQuery
  $( ".inner" ).append( "<p>Test</p>" );

//Result in the html

  <h2>Greetings</h2>
  <div class="container">
  <div class="inner">
    Hello
    <p>Test</p>
    </div>
    <div class="inner">
    Goodbye
    <p>Test</p>
    </div>
    </div>

- You can also select an element on the page and insert it into another:
    //jQuery
    $( ".container" ).append( $( "h2" ) );

Question 5

What is the prepend method?

Answer 5

• The prepend() method inserts specified content at the beginning of the selected elements.

Question 6

Function Syntaxis?

Answer 6

var udacityizer = function(s) {

s = s.replace("au","U");

return s; };

Question 7

6 Falsy values

Answer 7

• false
• 0
• ”” (empty string)
• null (Variable with no value)
• undefined (A nonexisting variable)
• NaN

Question 8

Array Syntaxis

Answer 8

• var myArray = [item1, item2];
• Example:
  var skills = ['’pig”, ‘‘cow”];

Question 9

for Syntaxis

Answer 9

• for (index = 0; index

Question 10

object Syntaxis

Answer 10

• There are no classes in JS.
• Example:
  var bio = {
  “name” : “James”,
  “age” : 32,
  “skills” : skills
  };

  //Acess bio name
   bio.name

  //Adding properties to obj 1
  bio.city = "Bogota";

  //Adding properties to obj 2
  bio["city"] = "Bogota";

Question 11

What is JSON?

Answer 11

• JavaScript Object Notation. JSON is a popular and simple format for storing and transferring nested or hierarchal data.
• JSON allows for objects (or data of other types) to be easily encapsulated within other objects.

Question 12

How to lint my JSON?

Answer 12

• You should copy and paste your code into a JSON linter like jsonlint.com to quickly and easily find syntax errors. A linter is a piece of software that analyzes code for syntax errors.

Question 13

JSON object example

Answer 13

var education = {
   "schools": [
     {
       "name": "university",
       "major": ["compu", "bio"]
     },
     {
       "name": "university",
       "major": ["compu", "bio"]
     },
   ]
};

Question 14

What is the DOM?

Answer 14

• Is part of the process of building websites, browsers convert all of the HTML they receive into a JavaScript object called the Document Object Model (DOM).

Question 15

Bracket notation

Answer 15

• planet[“name”]
• Bracket notation always works. Dot notation requires properties that begin with a letter and do not include special characters.