Beginning JavaScript®, Fourth Edition

Chapter 9. String Manipulation

In Chapter 4 you looked at the String object, which is one of the native objects that JavaScript makes available to you. You saw a number of its properties and methods, including the following:

• length — The length of the string in characters

• charAt() and charCodeAt() — The methods for returning the character or character code at a certain position in the string

• indexOf() and lastIndexOf() — The methods that allow you to search a string for the existence of another string and that return the character position of the string if found

• substr() and substring() — The methods that return just a portion of a string

• toUpperCase() and toLowerCase() — The methods that return a string converted to upper- or lowercase

In this chapter you'll look at four new methods of the String object, namely split(), match(), replace(), and search(). The last three, in particular, give you some very powerful text-manipulation functionality. However, to make full use of this functionality, you need to learn about a slightly more complex subject.

The methods split(), match(), replace(), and search() can all make use of regular expressions, something JavaScript wraps up in an object called the RegExp object. Regular expressions enable you to define a pattern of characters, which can be used for text searching or replacement. Say, for example, that you have a string in which you want to replace all single quotes enclosing text with double quotes. This may seem easy — just ...