Fires when the user presses a key.

Syntax

Inline HTML	<ELEMENT onkeydown = "handler" ... >	All platforms
Event property	object.onkeydown = handler	JScript only
	object.onkeydown = GetRef("handler")	Visual Basic Scripting Edition (VBScript) 5.0 or later only
Named script	<SCRIPT FOR = object EVENT = onkeydown>	Internet Explorer only

Event Information

Bubbles	Yes
Cancels	Yes
To invoke	Press any keyboard key.
Default action	Returns a number specifying the keyCode of the key that was pressed.

Event Object Properties

Although event handlers in the DHTML Object Model do not receive parameters directly, a handler can query an event object for data.

Available Properties

altKey	Sets or retrieves a value that indicates the state of the ALT key.
altLeft	Sets or retrieves a value that indicates the state of the left ALT key.
cancelBubble	Sets or retrieves whether the current event should bubble up the hierarchy of event handlers.
clientX	Sets or retrieves the x-coordinate of the mouse pointer's position relative to the client area of the window, excluding window decorations and scroll bars.
clientY	Sets or retrieves the y-coordinate of the mouse pointer's position relative to the client area of the window, excluding window decorations and scroll bars.
ctrlKey	Sets or retrieves the state of the CTRL key.
ctrlLeft	Sets or retrieves the state of the left CTRL key.
keyCode	Sets or retrieves the Unicode key code associated with the key that caused the event.
offsetX	Sets or retrieves the x-coordinate of the mouse pointer's position relative to the object firing the event.
offsetY	Sets or retrieves the y-coordinate of the mouse pointer's position relative to the object firing the event.
repeat	Retrieves whether the onkeydown event is being repeated.
returnValue	Sets or retrieves the return value from the event.
screenX	Retrieves the x-coordinate of the mouse pointer's position relative to the user's screen.
screenY	Sets or retrieves the y-coordinate of the mouse pointer's position relative to the user's screen.
shiftKey	Sets or retrieves the state of the SHIFT key.
shiftLeft	Retrieves the state of the left SHIFT key.
srcElement	Sets or retrieves the object that fired the event.
type	Sets or retrieves the event name from the event object.
x	Sets or retrieves the x-coordinate, in pixels, of the mouse pointer's position relative to a relatively positioned parent element.
y	Sets or retrieves the y-coordinate, in pixels, of the mouse pointer's position relative to a relatively positioned parent element.

Remarks

As of Microsoft® Internet Explorer 4.0, the onkeydown event fires for the following keys:

• Editing: DELETE, INSERT
• Function: F1 - F12
• Letters: A - Z (uppercase and lowercase)
• Navigation: HOME, END, LEFT ARROW, RIGHT ARROW, UP ARROW, DOWN ARROW
• Numerals: 0 - 9
• Symbols: ! @ # $ % ^ & * ( ) _ - + = < [ ] { } , . / ? \ | ' ` " ~
• System: ESC, SPACEBAR, SHIFT, TAB

As of Internet Explorer 5, the event also fires for the following keys:

• Editing: BACKSPACE
• Navigation: PAGE UP, PAGE DOWN
• System: SHIFT+TAB

As of Internet Explorer 5, this event can be canceled for the following keys and key combinations by specifying event.returnValue=false:

• Editing: BACKSPACE, DELETE
• Letters: A - Z (uppercase and lowercase)
• Navigation: PAGE UP, PAGE DOWN, END, HOME, LEFT ARROW, RIGHT ARROW, UP ARROW, DOWN ARROW
• Numerals: 0 - 9
• Symbols: ! @ # $ % ^ & * ( ) _ - + = < [ ] { } , . / ? \ | ' ` " ~
• System: SPACEBAR, ESC, TAB, SHIFT+TAB

You can cancel all keys that fire the onkeydown event in HTML Applications, including most accelerator keys, such as ALT+F4.

In Internet Explorer 4.0, you cannot cancel the onkeydown event, but you can use the onkeypress event to cancel keyboard events.

Example

This example uses the onkeydown event to cancel input from the keyboard.

<SCRIPT>
function fnTrapKD(){
if(oTrap.checked){
oOutput.innerText+="[trap = " + event.keyCode + "]";
event.returnValue=false;
}
else{
oOutput.innerText+=String.fromCharCode(event.keyCode);
}
}
</SCRIPT>
<INPUT TYPE="checkbox" ID="oTrap">
<INPUT ID="oExample" TYPE="text" onkeydown="fnTrapKD()">
<TEXTAREA ID="oOutput" ROWS="10" COLS="50">
</TEXTAREA>

This feature requires Microsoft® Internet Explorer 5 or later. Click the following icon to install the latest version. Then reload this page to view the sample.

Standards Information

This event is defined in HTML 4.0 .

Applies To

A, ACRONYM, ADDRESS, APPLET, AREA, B, BDO, BIG, BLOCKQUOTE, BODY, BUTTON, CAPTION, CENTER, CITE, CODE, CUSTOM, DD, DEL, DFN, DIR, DIV, document, DT, EM, FIELDSET, FONT, FORM, hn, HR, I, INPUT type=button, INPUT type=checkbox, INPUT type=file, INPUT type=image, INPUT type=password, INPUT type=radio, INPUT type=reset, INPUT type=submit, INPUT type=text, KBD, LABEL, LEGEND, LI, LISTING, MAP, MARQUEE, MENU, nextID, NOBR, OBJECT, OL, P, PLAINTEXT, PRE, Q, RT, RUBY, S, SAMP, SELECT, SMALL, SPAN, STRIKE, STRONG, SUB, SUP, TABLE, TBODY, TD, TEXTAREA, TFOOT, TH, THEAD, TR, TT, U, UL, VAR, XMP

See Also

onkeyup