KeyboardEvent keyCode Property
Example
Get the Unicode value of the pressed keyboard key:
var x = event.keyCode;
The result of x could be:
119 // 119 is the character
"w"
Try it Yourself »
More "Try it Yourself" examples below.
Definition and Usage
The keyCode property returns the Unicode character code of the key that triggered the onkeypress event, or the Unicode key code of the key that triggered the onkeydown or onkeyup event.
The difference between the two code types:
- Character codes - A number which represents an ASCII character
- Key codes - A number which represents an actual key on the keyboard
These types do not always mean the same thing; for example, a lower case "w" and an upper case "W" have the same keyboard code, because the key that is pressed on the keyboard is the same (just "W" = the number "87"), but a different character code because the resulting character is different (either "w" or "W", which is "119" or "87") - See "More Examples" below to better understand it.
Tip: To find out if the user is pressing a printable key (e.g. "a" or "5"), it is recommended to use this property on the onkeypress event. To find out if the user is pressing a function key (e.g. "F1", "CAPS LOCK" or "Home") use the onkeydown or onkeyup event.
Note: In Firefox, the keyCode property does not work on the onkeypress event (will only return 0). For a cross-browser solution, use the which property together with keyCode, e.g:
var x = event.which || event.keyCode; // Use either which or keyCode,
depending on browser support
Tip: For a list of all Unicode characters, please study our Complete Unicode Reference.
Tip: If you want to convert the returned Unicode value into a character, use the fromCharCode() method.
Note: This property is read-only.
Note: Both the keyCode and which property is provided for compatibility only. The latest version of the DOM Events Specification recommend using the key property instead (if available).
Tip: If you want to find out whether the "ALT", "CTRL", "META" or "SHIFT" key was pressed when a key event occured, use the altKey, ctrlKey, metaKey or shiftKey property.
Browser Support
| Property | |||||
|---|---|---|---|---|---|
| keyCode | Yes | Yes | Yes | Yes | Yes |
Syntax
event.keyCode
Technical Details
| Return Value: | A Number, representing either a Unicode character code or the Unicode key code |
|---|---|
| DOM Version: | DOM Level 2 Events |
More Examples
Example
Using onkeypress and onkeydown to demonstrate the differences between character codes and keyboard codes:
<input type="text" onkeypress="uniCharCode(event)" onkeydown="uniKeyCode(event)">
function uniCharCode(event) {
var char = event.which ||
event.keyCode;
document.getElementById("demo").innerHTML = "Unicode CHARACTER code: " +
char;
}
function uniKeyCode(event) {
var key = event.keyCode;
document.getElementById("demo2").innerHTML = "Unicode KEY code: " + key;
}
When pressing the "a" key on the keyboard (not using caps lock), the result of char and key will be:
Unicode CHARACTER code: 97
Unicode KEY
code: 65
Try it Yourself »
Example
Alert some text if the user presses the Escape key:
<input type="text" onkeydown="myFunction(event)">
function
myFunction(event) {
var x = event.keyCode;
if (x == 27) { // 27 is the ESC key
alert ("You pressed the Escape key!");
}
}
Try it Yourself »
Example
Convert the Unicode value into a character (does not work for function keys):
var x = event.keyCode; // Get the Unicode value
var y = String.fromCharCode(x);
// Convert the value into a character
Try it Yourself »
Related Pages
HTML DOM reference: KeyboardEvent key Property
HTML DOM reference: KeyboardEvent charCode Property
HTML DOM reference: KeyboardEvent which Property
Event Object
