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| <!DOCTYPE html> | |
| <html lang="en" xmlns="http://www.w3.org/1999/xhtml"> | |
| <head> | |
| <meta charset="utf-8" /> | |
| <script type="text/javascript"> | |
| //Variables are good to hold single values, but for cases where a variable should contain multiple values, | |
| //we would have to rely on arrays. A JavaScript array is a collection of items arranged in an order, | |
| //according to their index. Each item, in the array, is an element and has an index, which is used to access | |
| //that element. Arrays are like a bookshelf that holds more than one book; each book having its unique location. | |
| //Arrays are declared using the array literal notation [] | |
| var arrayOne = [1, 2, 3, 4]; | |
| alert(arrayOne[0]); | |
| var arrayTwo = ["One", "Two", "Three", "Four"]; | |
| alert(arrayTwo[0]); | |
| var multidimensionArray = [arrayOne, arrayTwo]; | |
| alert(multidimensionArray[1][2]); | |
| //The second way of declaring an array is by using the Array class. | |
| var bookshelf = new Array() | |
| //Objects are another way of handling data. In arrays the indexes are commonly numerical; | |
| //objects give us a robust way of assigning and retrieving data. Objects are derived from the object-oriented | |
| //programming concept; a programming paradigm that is very popular. Objects are a virtual representation of real-time data; | |
| //they allow us to organize our data into logical groups via properties and methods. | |
| //Properties describe the state of the object, while methods describe the behavior of the object. | |
| //Properties are a key-value pair that holds the information. Take a look at the following: | |
| //Objects | |
| var person = new Object(); | |
| person.firstname = "Nancy"; | |
| person.lastname = "G"; | |
| person.getFullName = function () { | |
| alert(person.firstname + ' ' + person.lastname); | |
| }; | |
| person.getFullName(); | |
| //In the previous example, we have instantiated a person object, and then added the firstname and lastname properties | |
| //that described the object. We added behavior to the object by creating a method called getFullName , | |
| //the method accessed the object properties, retrieved the data, and alerted the output onto the screen. | |
| //In this example the properties are accessed by the dot notation; we could also access a property by putting the | |
| //property name in square brackets similar to an array, but it is not popular. This is shown as follows: | |
| alert(person["firstname"]); | |
| //The second way of creating an object is by using the curly braces. Here we are introduced to the this keyword, | |
| //which provides a reference to the object's properties and methods, as shown in the following: | |
| var personObj = { | |
| "firstname": "Gale", | |
| "lastname": "D", | |
| "getFullName": function () { alert(this.firstname + ' ' + this.lastname); }, | |
| }; | |
| personObj.getFullName(); | |
| </script> | |
| <title></title> | |
| </head> | |
| <body> | |
| </body> | |
| </html> |
