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

This article is the sequel to How to check if a character is lowercase in Javascript, which tells how to know if a character is lowercase. As we have seen, the corresponding number codes for characters are referred to as ASCIIAmerican Standard Code For Information Interchange 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: 