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keydown
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keydown | onkeydown event

Fires when the user presses a key.

HTML 4.01 Specification, Section 18.2.3

 

Syntax

HTML Attribute <element onkeydown = "handler(event)">
Event Property object.onkeydown = handler;
attachEvent Method object.attachEvent("onkeydown", handler)
addEventListener Method object.addEventListener("keydown", handler, useCapture)

 

Event information

SynchronousNo
BubblesYes
CancelableYes

 

Event handler parameters

pEvtObj [in]

Type: IHTMLEventObj

Standards information

Remarks

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

As of Microsoft 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

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

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

Returns a number specifying the keyCode of the key that was pressed.

To invoke this event, do one of the following:

  • Press any keyboard key.

Examples

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

Code example: http://samples.msdn.microsoft.com/workshop/samples/author/dhtml/refs/onkeydown.htm


<script type="text/javascript">
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>

See also

a
abbr
acronym
address
applet
area
audio
b
bdo
big
blockQuote
body
button
canvas
caption
center
cite
code
custom
dd
del
dfn
dir
div
dl
document
dt
em
fieldSet
font
form
hn
hr
i
img
input type=button
input type=checkbox
input type=email
input type=file
input type=image
input type=number
input type=password
input type=radio
input type=range
input type=reset
input type=search
input type=submit
input type=tel
input type=text
input type=url
kbd
label
legend
li
listing
map
marquee
menu
nextID
noBR
object
ol
p
plainText
pre
q
rt
ruby
s
samp
select
small
source
span
strike
strong
sub
sup
table
tBody
td
textArea
tFoot
th
tHead
tr
tt
u
ul
var
video
window
xmp
onkeyup

 

 

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