How to detect Ctrl+V, Ctrl+C using JavaScript?
I need to restrict pasting in my textareas, end user should not copy and paste the content, user should only type text in textarea.
How can I achieve this?
How to detect Ctrl+V, Ctrl+C using JavaScript?
Asked Answered
I just did this out of interest. I agree it's not the right thing to do, but I think it should be the op's decision... Also the code could easily be extended to add functionality, rather than take it away (like a more advanced clipboard, or Ctrl+S triggering a server-side save).
$(document).ready(function() {
var ctrlDown = false,
ctrlKey = 17,
cmdKey = 91,
vKey = 86,
cKey = 67;
$(document).keydown(function(e) {
if (e.keyCode == ctrlKey || e.keyCode == cmdKey) ctrlDown = true;
}).keyup(function(e) {
if (e.keyCode == ctrlKey || e.keyCode == cmdKey) ctrlDown = false;
});
$(".no-copy-paste").keydown(function(e) {
if (ctrlDown && (e.keyCode == vKey || e.keyCode == cKey)) return false;
});
// Document Ctrl + C/V
$(document).keydown(function(e) {
if (ctrlDown && (e.keyCode == cKey)) console.log("Document catch Ctrl+C");
if (ctrlDown && (e.keyCode == vKey)) console.log("Document catch Ctrl+V");
});
});<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<h3>Ctrl+c Ctrl+v disabled</h3>
<textarea class="no-copy-paste"></textarea>
<br><br>
<h3>Ctrl+c Ctrl+v allowed</h3>
<textarea></textarea>Also just to clarify, this script requires the jQuery library.
EDIT: removed 3 redundant lines (involving e.which) thanks to Tim Down's suggestion (see comments)
EDIT: added support for Macs (CMD key instead of Ctrl)
Why the
keydown and keyup handlers on document? You can test for the Ctrl key in the $(".no-copy-paste").keydown handler. Also, there's no need for the e.keyCode || e.which bit: e.keyCode works in all browsers that e.which works in, so e.which will never be used. Perhaps you were thinking of how you get a character code from a keypress event? Finally, this will do nothing about pastes from the context or edit menus, but I suppose the OP didn't ask directly about that. –
Aftertaste @Tim: Ctrl key handlers on document to be general - as they may not want the ctrlDown variable to be exclusively linked to the no-copy-paste input(s). This is perhaps OTT. Thanks for the e.which tip - I've since spent half an hour researching the different use cases of e.keyCode and e.which with keydown() and keypress(), and what a mess (especially in firefox)! –
Radiochemistry
although this answers the question on how to detect ctrl-c and ctrl-v, other ways of pasting (rightclick-paste) are not (yet) detected this way. –
Jennie
jackocnr: I recommend Jan Wolter's JavaScript key handling article: unixpapa.com/js/key.html I've used it for reference many times and not found an error. –
Aftertaste
Dude! Thanks! This is exactly what I needed to enable users to select an "element" (calendar entry) in a web app I'm writing, hit ctrl + c to "copy" it, then ctrl+v to "paste" it, all without actually interacting with the allmighty blessed clipboard. ctrl+c I remember what they're clicked on, ctrl+v I duplicate it, everyone wins. –
Bainbrudge
I'm not an expert or anything, but i think it would probably be better to test for
e.metaKey or e.ctrlKey being true instead of assigning number values to the keys and testing those. –
Spirituel this wont work if you paste with right click and select paste –
Aweigh
Checkout this much more simple answer... #4604557 –
Schaper
Don't forget us Mac users! You'll want to listen not just for Ctrl's code 17 but also Cmd (224). –
Evensong
With jquery you can easy detect copy, paste, etc by binding the function:
$("#textA").bind('copy', function() {
$('span').text('copy behaviour detected!')
});
$("#textA").bind('paste', function() {
$('span').text('paste behaviour detected!')
});
$("#textA").bind('cut', function() {
$('span').text('cut behaviour detected!')
});
More information here: http://www.mkyong.com/jquery/how-to-detect-copy-paste-and-cut-behavior-with-jquery/
Unfortunately, this method will only fire on Firefox if text is selected –
Controvert
While it can be annoying when used as an anti-piracy measure, I can see there might be some instances where it'd be legitimate, so:
function disableCopyPaste(elm) {
// Disable cut/copy/paste key events
elm.onkeydown = interceptKeys
// Disable right click events
elm.oncontextmenu = function() {
return false
}
}
function interceptKeys(evt) {
evt = evt||window.event // IE support
var c = evt.keyCode
var ctrlDown = evt.ctrlKey||evt.metaKey // Mac support
// Check for Alt+Gr (http://en.wikipedia.org/wiki/AltGr_key)
if (ctrlDown && evt.altKey) return true
// Check for ctrl+c, v and x
else if (ctrlDown && c==67) return false // c
else if (ctrlDown && c==86) return false // v
else if (ctrlDown && c==88) return false // x
// Otherwise allow
return true
}
I've used event.ctrlKey rather than checking for the key code as on most browsers on Mac OS X Ctrl/Alt "down" and "up" events are never triggered, so the only way to detect is to use event.ctrlKey in the e.g. c event after the Ctrl key is held down. I've also substituted ctrlKey with metaKey for macs.
Limitations of this method:
- Opera doesn't allow disabling right click events
- Drag and drop between browser windows can't be prevented as far as I know.
- The
edit->copymenu item in e.g. Firefox can still allow copy/pasting. - There's also no guarantee that for people with different keyboard layouts/locales that copy/paste/cut are the same key codes (though layouts often just follow the same standard as English), but blanket "disable all control keys" mean that select all etc will also be disabled so I think that's a compromise which needs to be made.
If you use the ctrlKey property, you don't need to maintain state.
$(document).keydown(function(event) {
// Ctrl+C or Cmd+C pressed?
if ((event.ctrlKey || event.metaKey) && event.keyCode == 67) {
// Do stuff.
}
// Ctrl+V or Cmd+V pressed?
if ((event.ctrlKey || event.metaKey) && event.keyCode == 86) {
// Do stuff.
}
// Ctrl+X or Cmd+X pressed?
if ((event.ctrlKey || event.metaKey) && event.keyCode == 88) {
// Do stuff.
}
}
THIS is the correct answer! The event has a property ctrlKey = true if a key has been pressed with it. We do not need any extra events. –
Mennonite
This is what exactly I'm looking for –
Pluvious
On inputs, the .val() is empty –
Cottontail
But keyCode is deprecated. –
Votive
There's another way of doing this: onpaste, oncopy and oncut events can be registered and cancelled in IE, Firefox, Chrome, Safari (with some minor problems), the only major browser that doesn't allow cancelling these events is Opera.
As you can see in my other answer intercepting Ctrl+V and Ctrl+C comes with many side effects, and it still doesn't prevent users from pasting using the Firefox Edit menu etc.
function disable_cutcopypaste(e) {
var fn = function(evt) {
// IE-specific lines
evt = evt||window.event
evt.returnValue = false
// Other browser support
if (evt.preventDefault)
evt.preventDefault()
return false
}
e.onbeforepaste = e.onbeforecopy = e.onbeforecut = fn
e.onpaste = e.oncopy = e.oncut = fn
}
Safari still has some minor problems with this method (it clears the clipboard in place of cut/copy when preventing default) but that bug appears to have been fixed in Chrome now.
See also: http://www.quirksmode.org/dom/events/cutcopypaste.html and the associated test page http://www.quirksmode.org/dom/events/tests/cutcopypaste.html for more information.
This answer is best in my opinion, mainly because users can change their copy/paste key bindings. This is unlikely, but it's better to cover all possible cases. –
Marleah
Live Demo : http://jsfiddle.net/abdennour/ba54W/
$(document).ready(function() {
$("#textA").bind({
copy : function(){
$('span').text('copy behaviour detected!');
},
paste : function(){
$('span').text('paste behaviour detected!');
},
cut : function(){
$('span').text('cut behaviour detected!');
}
});
});
Short solution for preventing user from using context menu, copy and cut in jQuery:
jQuery(document).bind("cut copy contextmenu",function(e){
e.preventDefault();
});
Also disabling text selection in CSS might come handy:
.noselect {
-webkit-touch-callout: none;
-webkit-user-select: none;
-khtml-user-select: none;
-moz-user-select: none;
-ms-user-select: none;
user-select: none;
}
Another approach (no plugin needed) it to just use ctrlKey property of the event object that gets passed in. It indicates if Ctrl was pressed at the time of the event, like this:
$(document).keypress("c",function(e) {
if(e.ctrlKey)
alert("Ctrl+C was pressed!!");
});
See also jquery: keypress, ctrl+c (or some combo like that).
element.addEventListener('keydown', function (e) {
if (e.key == 'c' && e.ctrlKey) {
e.preventDefault(); // prevent from copying
}
if (e.key == 'v' && e.ctrlKey) {
e.preventDefault(); // prevent from pasting
}
}
Your answer could be improved by adding more information on what the code does and how it helps the OP. –
Blancablanch
That's a silly comment. Read the thread and see. –
Concede
'Threads' do not exist on Stack Overflow, each answer provided to a question must provide a short code snippet along with an explanation of what the code does and how it solves the problem. Also, if there are other answers some information on why you think your solution is better than some of the other solutions is preferred. –
Blancablanch
Read the question and compare answers - just like anybody does looking for an answer here. Then speak. Otherwise Your comment is rude and condescending. –
Concede
And stackoverflow team is writing about losing visitors. Wonder why, when they have such gems on their side. –
Concede
instead of onkeypress, use onkeydown.
<input type="text" onkeydown="if(event.ctrlKey && event.keyCode==86){return false;}" name="txt">
You can use this code for rightclick, CTRL+C, CTRL+V, CTRL+X detect and prevent their action
$(document).bind('copy', function(e) {
alert('Copy is not allowed !!!');
e.preventDefault();
});
$(document).bind('paste', function() {
alert('Paste is not allowed !!!');
e.preventDefault();
});
$(document).bind('cut', function() {
alert('Cut is not allowed !!!');
e.preventDefault();
});
$(document).bind('contextmenu', function(e) {
alert('Right Click is not allowed !!!');
e.preventDefault();
});
If anyone is interested in a simple vanilla JavaScript approach, see below.
Fiddle Link: DEMO
let ctrlActive = false;
let cActive = false;
let vActive = false
document.body.addEventListener('keyup', event => {
if (event.key == 'Control') ctrlActive = false;
if (event.code == 'KeyC') cActive = false;
if (event.code == 'KeyV') vActive = false;
})
document.body.addEventListener('keydown', event => {
if (event.key == 'Control') ctrlActive = true;
if (ctrlActive == true && event.code == 'KeyC') {
// this disables the browsers default copy functionality
event.preventDefault()
// perform desired action(s) here...
console.log('The CTRL key and the C key are being pressed simultaneously.')
}
if (ctrlActive == true && event.code == 'KeyV') {
// this disables the browsers default paste functionality
event.preventDefault()
// perform desired action(s) here...
console.log('The CTRL key and the V key are being pressed simultaneously.')
}
})
The code above would disable the default copy in the browser. If you'd like keep the copy functionality in the browser, just comment out this bit: event.preventDefault() and you can then run any desired actions while allowing the user to copy content.
I wrote a jQuery plugin, which catches keystrokes. It can be used to enable multiple language script input in html forms without the OS (except the fonts). Its about 300 lines of code, maybe you like to take a look:
Generally, be careful with such kind of alterations. I wrote the plugin for a client because other solutions weren't available.
Don't forget that, while you might be able to detect and block Ctrl+C/V, you can still alter the value of a certain field.
Best example for this is Chrome's Inspect Element function, this allows you to change the value-property of a field.
A hook that allows for overriding copy events, could be used for doing the same with paste events. The input element cannot be display: none; or visibility: hidden; sadly
export const useOverrideCopy = () => {
const [copyListenerEl, setCopyListenerEl] = React.useState(
null as HTMLInputElement | null
)
const [, setCopyHandler] = React.useState<(e: ClipboardEvent) => void | null>(
() => () => {}
)
// appends a input element to the DOM, that will be focused.
// when using copy/paste etc, it will target focused elements
React.useEffect(() => {
const el = document.createElement("input")
// cannot focus a element that is not "visible" aka cannot use display: none or visibility: hidden
el.style.width = "0"
el.style.height = "0"
el.style.opacity = "0"
el.style.position = "fixed"
el.style.top = "-20px"
document.body.appendChild(el)
setCopyListenerEl(el)
return () => {
document.body.removeChild(el)
}
}, [])
// adds a event listener for copying, and removes the old one
const overrideCopy = (newOverrideAction: () => any) => {
setCopyHandler((prevCopyHandler: (e: ClipboardEvent) => void) => {
const copyHandler = (e: ClipboardEvent) => {
e.preventDefault()
newOverrideAction()
}
copyListenerEl?.removeEventListener("copy", prevCopyHandler)
copyListenerEl?.addEventListener("copy", copyHandler)
copyListenerEl?.focus() // when focused, all copy events will trigger listener above
return copyHandler
})
}
return { overrideCopy }
}
Used like this:
const customCopyEvent = () => {
console.log("doing something")
}
const { overrideCopy } = useOverrideCopy()
overrideCopy(customCopyEvent)
Every time you call overrideCopy it will refocus and call your custom event on copy.
Another simple way using Jquery:
$(document).keydown( function(e)
{
if (e.ctrlKey && e.key == 'c')
{
console.log('got ctrl c');
}
else if (e.ctrlKey && e.key == 'v')
{
console.log('got ctrl v');
}
});
i already have your problem and i solved it by the following code .. that accept only numbers
$('#<%= mobileTextBox.ClientID %>').keydown(function(e) {
///// e.which Values
// 8 : BackSpace , 46 : Delete , 37 : Left , 39 : Rigth , 144: Num Lock
if (e.which != 8 && e.which != 46 && e.which != 37 && e.which != 39 && e.which != 144
&& (e.which < 96 || e.which > 105 )) {
return false;
}
});
you can detect Ctrl id e.which == 17
Important note
I was using e.keyCode for a while and i detected that when i press Ctrl+., This attribute returns a wrong number, 190, while the ascii code of . is 46!
So you should use e.key.toUpperCase().charCodeAt(0) instead of e.keyCode.
$(document).keydown(function(event) {
let keyCode = e.key.toUpperCase().charCodeAt(0);
...
}
That 46! is not a factorial. :) –
Stiegler
This is a very old post but everyone's answers were all using jQuery and were all over engineered.
OP wanted to prevent people from pasting in multiple textareas, this is a more modern approach.
const targets = document.querySelectorAll( 'textarea' );
for( const target of targets ) target.addEventListener( 'paste', e => e.preventDefault() );<textarea placeholder="You can't paste in me"></textarea>
<textarea placeholder="You can't paste in me either"></textarea>You can listen to the keypress event, and halt the default event (entering the text) if it matches the specific keycodes
There is some ways to prevent it.
However the user will be always able to turn the javascript off or just look on the source code of the page.
Some examples (require jQuery)
/**
* Stop every keystroke with ctrl key pressed
*/
$(".textbox").keydown(function(){
if (event.ctrlKey==true) {
return false;
}
});
/**
* Clear all data of clipboard on focus
*/
$(".textbox").focus(function(){
if ( window.clipboardData ) {
window.clipboardData.setData('text','');
}
});
/**
* Block the paste event
*/
$(".textbox").bind('paste',function(e){return false;});
Edit: How Tim Down said, this functions are all browser dependents.
This has a number of problems: first, it won't work in browsers that don't have a
paste event, which includes all versions of Firefox prior to version 3. Second, window.clipboardData is IE only and I believe is now disabled by default in IE. Third, disabling all keydown events where the Ctrl key is pressed is excessive: you prevent useful keyboard shortcuts such as Ctrl-A (select all) and Ctrl-Z (undo). Fourth, as mentioned by others, this is a really bad thing to do. –
Aftertaste You are right about that don't working on every browser. Nobody The ctrl block is annoying indeed. It was handy once when a client wanted to block the "Confirmation Email and Password" field. –
Inexperience
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name="email", you automatically copy over to thename="repeat-email", and if you don't detect it, you disallow pasting in the verification field. – Hultin