Javascript String object

A String is a grouping of characters sorrounded by double quotes such as "this is a string". The String object is used to work with such entitites.

This lesson focuses on:

Instantiating a String object
Properties of the String object
Methods of the String object

Instantiating a String object

A String object is instantiated using the new keyword.

Example:

var aString = new String("Here is some text");

Alternatively, a String object can be instantiated by sorrounding text in double quotes and assigning it to a variable.

var anotherString = "Here is some more text";

Properties of the String object

length

Returns the numbers of characters in a string.

Example:

var aString = "World wide web"

//print the number of characters in
//the aString string
document.write(aString.length);

Output:

Methods of the String object

toLowerCase()

Displays a String in lowercase letters.

Example:

var message = "Hello, It Is A Sunny DAY.";

//print the message string
//in lowercase letters
document.write(aString.toLowerCase());

Output:

hello, it is a sunny day.

concat()

Joins two or more strings.

Example:

var description1 = "Javascript is a scripting 
                    language developed by Netscape ";
var description2 = "used to provide dynamic and 
                    interactive content on webpages.";

//join the description1 and description2 strings
//and print them
document.write(description1.concat(description2));

Output:

Javascript is a scripting language developed by Netscape used to provide dynamic and interactive content on webpages.

substr(startPoint, numToExtract)
Extracts a substring from a string.

Example:
```
var message = "Javascript is cool!";

//print the first four characters
//of the message string
document.write(message.substr(0, 4));
```
Output:

Java

The substr() method takes two parameters. The first parameter is a numeric value indicating where in the string to begin extracting characters from. The second parameter is also a numeric value indicating how many characters in the string to extract.

italics()

Displays a string in italics.

Example:

var text = "This text will be displayed in italics"

//print the "text" string in italics
document.write(text.italics());

Output:

This text will be displayed in italics