The ABCs of JavaScript Strings: Everything You Need to Know

In JavaScript, a string is a sequence of characters enclosed in single or double quotes. A string can be any text inside the quotation marks. A string can be as simple as a single character or word or as complex as an entire paragraph.

JavaScript strings are used for storing and manipulating text. They are also used for representing text values in HTML. All string manipulation methods return a new string and do not modify the original string. This blog post will cover the basics of working with strings in JavaScript so that you can get started manipulating text in your own web projects.

String Properties and Methods

In JavaScript, there are two properties that are used to access the length of a string: the .length property and the .size() method. The .length property returns the number of characters in a string, while the size() method returns the number of bytes needed to store the string in memory. Look at strings in javascript.

There are also several methods that can be used to manipulate strings. Some of the most commonly used string methods are listed below:

concat(): This method concatenates (joins) two or more strings and returns a new joined string.

split(): This method splits a string into an array of substrings and returns the new array.

substr(): This method extracts parts of a string and returns the extracted part in a new string.

toLowerCase(): This function converts any uppercase letters in a string to lowercase and returns the new all-lowercase string..

toUpperCase(): This function changes all lowercase letters in a string to uppercase and returns the new uppercase version.

indexOf(): This method returns the index within a string at which a specified value first occurs, or -1 if it does not occur.

Strings in JavaScript are immutable, which means that once a string is created, it cannot be changed. However, there are methods that can be used to perform operations on strings that appear to change the original string.

For example, the .concat() method can be used to add two strings together. When this method is called on a string, it returns a new string that is the result of concatenating the two strings. The original string is not modified.

Strings can be compared using the comparison operators (>, =, <=, and so on). When comparing strings, JavaScript will compare the character codes at each index in the strings. The character codes are numerical values that represent the characters in a string.

For example, the character code for “A” is 65, and the character code for “a” is 97. Comparing two strings using the comparison operators will result in a Boolean value (true or false).

JavaScript also has a built-in method for comparing strings, called .localeCompare(). This method returns a number that indicates whether a string comes before or after another string in alphabetical order.

A value of -0 indicates that the two strings are equal, a value of less than 0 indicates that the first string comes before the second string in alphabetical order, and a value of greater than 0 indicates that the first string comes after the second string in alphabetical order.


JavaScript offers developers many ways to work with strings—from simple properties like .length to more complex methods like .concat() and .split(). By understanding how to use these properties and methods, you’ll be well on your way to being able to manipulate text values in your web projects like a pro!


Ivy Skye Marshall: Ivy, a social justice reporter, covers human rights issues, social movements, and stories of community resilience.