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JavaScript String charCodeAt() Method
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