This article is the sequel to [How to check if a character is lowercase in Javascript](https://www.educative.io/answers/type-codes-in-python), which tells how to know if a character is lowercase.

As we have seen, the corresponding number codes for characters are referred to as **#key# ASCII: American Standard Code For Information Interchange #key# codes**. These codes can be found through the `event.charCode` property of a key on your keyboard, when an `event` of `keypress` is attached to the keys on your keyboard.

#   
## The `event.charCode` property
This property allows us to know the value of a character or key on your keyboard. As we saw from the preceding article, characters that are uppercase can be known through their ranges.

See an example below:



<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <label>Fill in the text box</label><br>
    <input type="text" name="char" id="char">
    <span id="code" style="color: green;"></span>
</body>
</html>

codemirror

The JavaScript code that does the function above is shown below:


document.getElementById("char").addEventListener("keypress", (event) => {
  document.getElementById("code").innerText =
    `character ${event.key} =  code ${event.charCode}`
})

#   
#  Range of uppercase characters
**Uppercase characters** have their range from 65 - 90.

This means that characters that do not fall within this range are not uppercase, and this determines which character is uppercase.


##  
## Example


<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Uppercase characters</title>
</head>
<body>
    <label>Fill in the text box</label><br>
    <input type="text" name="char" id="char">
    <span id="message" style="color: red;"></span>
</body>
</html>

let message = document.getElementById("message")
document.getElementById("char").addEventListener("keypress", (event) => {
  if (event.charCode < 65 || event.charCode > 90) {
    message.style.color = "red"
    message.innerText =
      `${event.key} is not UPPERCASE`
  } else {
    message.style.color = "green"
    message.innerText =
      `${event.key} is UPPERCASE`
  }
})


In the JavaScript code above, we checked if the `event.charCode` falls within the range of 65-90. This tells if the character entered is UPPERCASE or not.

How to check if a character is uppercase in JavaScript

The event.charCode property

Range of uppercase characters

Example

The `event.charCode` property