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new RegExp

This code matches the letter

“blue”

Alternatively, you can specify the character code using octal instead of hex by including the octal charac-

ters after a backslash. For example,

is equal to octal 142, so this will work:

var sColor = “blue”;

var reB = /\142/;

alert(reB.test(sColor)); //outputs “true”

To represent a character using Unicode, you must specify a four-digit hexadecimal representation of the

character code. So

becomes

\u0062

var sColor = “blue”;

var reB = /\u0062/;

alert(reB.test(sColor)); //outputs “true”

Note that to use this method of representing characters with the

RegExp

constructor, you still need to

include a second backslash:

var sColor = “blue”;

var reB = new RegExp(“\\u0062”)/;

alert(reB.test(sColor)); //outputs “true”

Additionally, there are a number of predefined special characters, which are listed in the following table:

Character

Description

The tab character

The new line character

The carriage return character

The form feed character

The alert character

The escape character

The control character corresponding to

Backspace character

Vertical tab character

Null character

All of these characters must also be double-escaped in order to use them with the

RegExp

constructor.

Suppose you want to remove all new line characters from a string (a common task when dealing with

user-input text). You can do so like this:

var sNewString = sStringWithNewLines.replace(/\n/g, “”);

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