A string can be any text inside quotes. You can use single or double quotes:
You can use quotes inside a string, as long as they don't match the quotes surrounding the string:
The length of a string is found in the built in property length:
The string will be chopped to "We are the so-called ".
The solution to avoid this problem, is to use the \ escape character.
The backslash escape character turns special characters into string characters:
The escape character (\) can also be used to insert other special characters in a string.
This is the lists of special characters that can be added to a text string with the backslash sign:
For best readability, programmers often like to avoid code lines longer than 80 characters.
You can also break up a code line within a text string with a single backslash:
However, you cannot break up a code line with a backslash:
But strings can also be defined as objects with the keyword new: var firstName = new String("John")
Don't create strings as objects.
It slows down execution speed, and produces nasty side effects:
When using the == equality operator, equal strings looks equal:
When using the === equality operator, equal strings are not equal, because the === operator expects equality in both type and value.
Or ever worse. Different objects cannot be compared:
|Objects cannot be compared.|
Primitive values, like "John Doe", cannot have properties or methods (because they are not objects).
String methods are covered in next chapter.
|constructor||Returns the function that created the String object's prototype|
|length||Returns the length of a string|
|prototype||Allows you to add properties and methods to an object|
|charAt()||Returns the character at the specified index (position)|
|charCodeAt()||Returns the Unicode of the character at the specified index|
|concat()||Joins two or more strings, and returns a copy of the joined strings|
|fromCharCode()||Converts Unicode values to characters|
|indexOf()||Returns the position of the first found occurrence of a specified value in a string|
|lastIndexOf()||Returns the position of the last found occurrence of a specified value in a string|
|localeCompare()||Compares two strings in the current locale|
|match()||Searches a string for a match against a regular expression, and returns the matches|
|replace()||Searches a string for a value and returns a new string with the value replaced|
|search()||Searches a string for a value and returns the position of the match|
|slice()||Extracts a part of a string and returns a new string|
|split()||Splits a string into an array of substrings|
|substr()||Extracts a part of a string from a start position through a number of characters|
|substring()||Extracts a part of a string between two specified positions|
|toLocaleLowerCase()||Converts a string to lowercase letters, according to the host's locale|
|toLocaleUpperCase()||Converts a string to uppercase letters, according to the host's locale|
|toLowerCase()||Converts a string to lowercase letters|
|toString()||Returns the value of a String object|
|toUpperCase()||Converts a string to uppercase letters|
|trim()||Removes whitespace from both ends of a string|
|valueOf()||Returns the primitive value of a String object|