Get the Unicode value of the pressed keyboard key:
The result of x could be:
More "Try it Yourself" examples below.
The which 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:
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: The which property is not supported in IE8 and earlier. For these browser versions, you can use the keyCode property. However, the keyCode property does not work on the onkeypress event in Firefox. For a cross-browser solution, you can use the following code:
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 which and keyCode 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.
The numbers in the table specify the first browser version that fully supports the property.
Property | |||||
---|---|---|---|---|---|
which | Yes | 9.0 | Yes | Yes | Yes |
Return Value: | A Number, representing either a Unicode character code or the Unicode key code |
---|---|
DOM Version: | DOM Level 2 Events |
Using onkeypress and onkeydown to demonstrate the differences between character codes and keyboard codes:
When pressing the "a" key on the keyboard (not using caps lock), the result of char and key will be:
Alert some text if the user presses the Escape key:
Convert the Unicode value into a character (does not work for function keys):
HTML DOM reference: KeyboardEvent key Property
HTML DOM reference: KeyboardEvent keyCode Property
HTML DOM reference: KeyboardEvent charCode Property