JavaScript - Data Types and this key word (Part 2)
JavaScript Data types
JavaScript Data
types one of the most fundamental characteristics of a programming language is
the set of data types it supports. These are the type of values that can be
represented and manipulated in a programming language.
JavaScript allows you to work with three
primitive data types:
- Numbers,
e.g., 123, 120.50 etc.
- Strings of text, e.g. "This text string" etc.
- Boolean,
e.g. true or false.
JavaScript also defines two trivial data
types, null and undefined, each of which defines only a single value. In
addition to these primitive data types, JavaScript supports a composite data
type known as an object. We will cover objects in detail in a separate chapter.
Note: Java does not make a distinction between
integer values and floating-point values. All numbers in JavaScript are
represented as floating-point values. JavaScript represents numbers using the
64-bit floating-point format defined by the IEEE 754 standard.
JavaScript This
Key Word
The JavaScript this keyword refers to the object it belongs to. It has different values depending on where it is used:
- In a method, this refers to the owner object.
- Alone, this refers to the global object.
- In a function, this refers to the global object.
- In a function, in strict mode, this is undefined.
- In an event, this refers
to the element that received the event.
- Methods like call (), and apply () can refer this to any object.
this in a Method: In an object method, this refers to the "owner" of the method.
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