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JavaScript String charCodeAt() Method

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The JavaScript String charCodeAt() method returns an integer between 0 to 65535 at the specified index. That integer value is considered as a Unicode of the individual character. The index starts from 0 and ends with str.length-1.

If the index parameter value is not in the range of 0 to str.length-1, it will return 'NaN'.

Syntax

Following is the syntax of JavaScript String charCodeAt() method −

charCodeAt(index)

Parameters

This method takes an optional parameter called 'index', which is explained below −

  • index − The index (position) of the character.

Return value

This method returns a Unicode of the character at the specified index.

Example 1

When we omit the index parameter, this method assumes its index parameter default value as 0 and returns the Unicode of the first character, 'T', in the given string "Tutorials Point".

<html>
<head>
<title>JavaScript String charCodeAt() Method</title>
</head>
<body>
<script>
   const str = "Tutorials Point";
   document.write("String value = ", str);
   document.write("<br>The character code ", str.charCodeAt(), " is equal to ", str.charAt());
</script>
</body>
</html>

Output

The above program returns Unicode as 84 for character 'T'.

String value = Tutorials Point
The character code 84 is equal to T

Example 2

If we pass the index value as 6 to this method, it returns a Unicode of a character at the specified index.

Following is another example of the JavaScript String charCodeAt() method. Here, we are using this method to retrieve the Unicode of a character in the given string "Hello World" at the specified index 6.

<html>
<head>
<title>JavaScript String charCodeAt() Method</title>
</head>
<body>
<script>
   const str = "Hello World";
   document.write("String value = ", str);
   let index = 6;
   document.write("<br>Index value = ", index);
   document.write("<br>The character at ", index, "th position is: ", str.charAt(index));
   document.write("<br>The Unicode of a character '", str.charAt(index), "' is: ", str.charCodeAt(index));
</script>
</body>
</html>

Output

After executing the above program, it will return Unicode 87 of a character 'W'.

String value = Hello World
Index value = 6
The character at 6th position is: W
The Unicode of a character 'W' is: 87

Example 3

When the index parameter is not between 0 to str.length-1, this method returns 'NaN'.

We can verify the above fact statement that the charCodeAt() method returns 'NaN' if the index parameter is out of the range of 0 to str.length-1 by executing the program below.

<html>
<head>
<title>JavaScript String charCodeAt() Method</title>
</head>
<body>
<script>
   const str = "JavaScript";
   document.write("String value = ", str);
   let index = 15;
   document.write("<br>Index value = ", index);
   document.write("<br>The character at ", index, "th position is: ", str.charAt(index));
   document.write("<br>The Unicode of a character '", str.charAt(index), "' is: ", str.charCodeAt(50));
</script>
</body>
</html>

Output

This method will return 'NaN', because the index value is out of range.

String value = JavaScript
Index value = 15
The character at 15th position is:
The Unicode of a character '' is: NaN
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