Chapter 16 - Javascript and PHP Validation and Error Handling

Question 1

Are JavaScript functions and variable names case-sensitive or case-insensitive?

Answer 1

JavaScript functions and variable names are case-sensitive. The variables Count, count, and COUNT are all different.

Question 2

How can you write a function that accepts and processes an unlimited number of parameters?

Answer 2

To write a function that accepts and processes an unlimited number of parameters, access parameters through the arguments array, which is a member of all functions.

Question 3

Name a way to return multiple values from a function.

Answer 3

One way to return multiple values from a function is to place them all inside an array and return the array.

Question 4

When you’re defining a class, what keyword do you use to refer to the current object?

Answer 4

When defining a class, use the this keyword to refer to the current object.

Question 5

Do all the methods of a class have to be defined within the class definition?

Answer 5

The methods of a class do not have to be defined within a class definition. If a method is defined outside the constructor, the method name must be assigned to the this object within the class definition.

Question 6

What keyword is used to create an object?

Answer 6

New objects are created via the new keyword.

Question 7

How can you make a property or method available to all objects in a class without replicating the property or methodwithin the object?

Answer 7

You can make a property or method available to all objects in a class without replicating the property or method withi the object by using the prototype keyword to create a single instance, which is then passed by reference to all the objects in a class.

Question 8

How can you create a multidimensional array?

Answer 8

To create a multidimensional array, place subarrays inside the main array.

Question 9

What syntax is used to create an associative array?

Answer 9

The suntax you would use to create an associative array is key : value, within curly braces, as in the following:

//assocaray = 
//{
//"forename" : //"Paul", 

//”surname” : //”McCartney”

//}

Question 10

Write a statement to sort an array of numbers in descending numerical order.

Answer 10

A statement to sort an array of numbers into descending numerical order would look like this:

//numbers.sort(function(a, b){ return b - a })