Restore default value of arrows key - javascript

I'm using a script (impress.js) that bins some particular action to keyup and keydown events for left, right, up and down arrows.
In some particular moments (for example while typing in a textarea) I want back the default behaviour for the arrows.
I tried without success with
$("a#show-ta").click( function() {
document.addEventListener("keydown", function ( event ) {
if (event.keyCode >= 37 && event.keyCode <= 40) {
return;
}
});
document.addEventListener("keyup", function ( event ) {
if (event.keyCode >= 37 && event.keyCode <= 40) {
return;
}
});
});
where a#show-ta is the button that shows my textarea.

You want to prevent the keypress from bubbling up to the document where (I assume) Impress binds its handlers:
$("textarea").on('keyup keydown keypress', function(e) {
e.stopPropagation();
});

If you need the event in a specific zone, such as a texarea, you should stop the propagation of the event like this :
$('textarea').keydown( function(ev) {
ev.stopPropagation();
});
If the events are necessary for the whole page but you want to exclude while you are in a textarea, for example, you could raise a flag which you would validate in the event.
var keydownActivated = true;
$('textarea').keydown( function(ev) {
if (keydownActivated) {
ev.preventDefault();
// dostuff
}
});

This will more or less get you where you are going. Create a flag that tracks whether or not the textarea has focus, and check that flag in your current key press event handlers. I can't see all of your code, so this is just a simple example:
var textareaHasFocus = false;
var textarea = document.querySelector('#yourTextarea');
textarea.addEventListener('focus', function(event) {
textareaHasFocus = true;
}, false);
textarea.addEventListener('blur', function(event) {
textareaHasFocus = false;
}, false);
document.addEventListener("keydown", function ( event ) {
if (textareaHasFocus) return true;
// your current keyboard handler
});
document.addEventListener("keyup", function ( event ) {
if (textareaHasFocus) return true;
// your current keyboard handler
});

Related

Pressing space on iframe scrolls parent page down, how to prevent that without breaking keyup event

My iframe game is reading the keyboard including space, but on some browsers (Firefox, Safari) pressing Space also scrolls my page down, that causes my game to partially go out of screen. Sometimes it seems the page even scrolls back up when some other keys are pressed...
My game handles keypresses on "keyup" event.
input.addEventListener("keyup", function (e) {
//game handles all keys including space here
}
Because of using keyup event, this answer is not suitable to prevent space ;
Pressing spacebar scrolls page down?
If I add this code, my game does not receive keyup events:
window.onkeydown = function(e) {
return !(e.keyCode == 32);
};
When I add this code above to parent html page, having ifreme, it only works if keyboard focus is clicked to parent html. When focus is inside iframe, the code does not work.
It seems above code fixed issue for Safari!
The onkeypress event fires the browser scrolling. You can call preventDefault in this event, and the keyup and keydown events will continue to fire as intended.
window.onkeypress = function(e) {
if (e.keyCode == 32) {
e.preventDefault();
}
};
window.onkeyup = function(e) {
console.log("Space key up!")
};
You need preventDefault
window.addEventListener('keydown', (e) => {
if (e.keyCode === 32) {
e.preventDefault();
}
});
See this codepen for a demo: https://codepen.io/xurei/pen/MWyveEp
You have to find the right window object first
function getIframeWindow(iframe_object) {
var doc;
if (iframe_object.contentWindow) {
return iframe_object.contentWindow;
}
if (iframe_object.window) {
return iframe_object.window;
}
if (!doc && iframe_object.contentDocument) {
doc = iframe_object.contentDocument;
}
if (!doc && iframe_object.document) {
doc = iframe_object.document;
}
if (doc && doc.defaultView) {
return doc.defaultView;
}
if (doc && doc.parentWindow) {
return doc.parentWindow;
}
return undefined;
}
var myFrame = document.getElementById('targetFrame');
var frame_win = getIframeWindow(myFrame);
and then add the listeners to stop the spacebar event from bubbling up.
if (frame_win) {
var preventSpace = (e) => {
if (e.keyCode === 32) {
e.preventDefault();
}
};
frame_win.addEventListener('keydown', preventSpace);
frame_win.addEventListener('keyup', preventSpace);
frame_win.addEventListener('keypress', preventSpace);
}

addEventListener on keyup javascript once

I want to run countup(); and random(); function after I hit enter on my keyboard. But I wanna make that it's only work for the first time.I mean when first time i hit enter, it will run that function. But if those function already run and I hit enter again, it'll never effect anything.
Here's my code :
addEventListener("keydown", function(e){
if (e.keyCode === 13) {
countup();
random();
}
});
Anyone can help me? Thanks.
Do something like this
// Create a named function as your event handler
var myFunction = function (e) {
if (e.keyCode === 13) {
// Do your stuff here
countup();
random();
// Remove event listener so that next time it is not triggered
removeEventListener("keydown", myFunction);
}
};
// Bind "keydown" event
addEventListener("keydown", myFunction);
Idea is user a global variable, set it after firing event.
var is_fired = false;
addEventListener("keydown", function(e){
if (e.keyCode === 13 && is_fired == false) {
countup();
random();
is_fired = true
}
});
You can make click event listener work only once after trigger it.you just need to add another argument to addEventListener() which is {once:true}and it will work as expected:
addEventListener("keydown", function(e){
if (e.keyCode === 13) {
countup();
random();
}
},{once: true});
Check my question it's similar to your case.
Also you can just use removeEventListener()method but you should defined your Anonymous function before as external function like myKeyPressed() and then inside if condition remove event Listener from your element:
element.removeEventListener("keydown", myKeyPressed);
var is_clicked = false;
addEventListener("keydown", function(e){
if (e.keyCode === 13 && !is_clicked) {
countup();
random();
is_clicked = true;
}
});
There is a removeEventListener function in javascript but it's tricky to implement that inside the function you are calling on addEventListener.
Try this, it worked in jsfiddle.
addEventListener("keydown", function(e){
if (e.keyCode === 13) {
alert("i did it");
this.removeEventListener('keydown',arguments.callee,false);
}
});
You can add a variable to check the status of your keydown.
The first time you use it, set it up to true. So you will only have this function triggered once.
var n = document.getElementById("txtInput"),
r = document.getElementById("result"),
loadFlag = true;
n.addEventListener("keyup", function(e) {
if (e.keyCode === 13 && loadFlag ) {
countup(r);
random(r);
loadFlag = false;
}
}, false);
To add keydown to an element in your HTML code.
element.addEventListener("keydown", event => {
//check if event is cancelable because not all event can be cancelled
if(event.cancelable)
{
//this prevent element from executing the default event when user click
event.preventDefault()
if(event.keycode === 13){ //write your statement here }
}
}
for more https://www.w3schools.com/jsref/event_preventdefault.asp

on down arrow KeyPress, click event is getting fired

on down arrow keypress , click event is getting fired, event.keycode is undefined
$(".dropdown:not(.li-search) a.dropdown-toggle", ".navbar-collapse").on("click", function(event) {
var target = $(this).attr("target");
if (event.keyCode !== '40'){
if (!$(".li-menu").is(":visible") && target === undefined) {
location.href=this.href;
} else {
window.open(this.href, '_blank');
}
}
});
in this code i am trying to open main menu in new tab , but external link is getting open on down arrow keypress
call preventDefault() function.
$(".dropdown:not(.li-search) a.dropdown-toggle", ".navbar-collapse").on("click", function(event) {
event.preventDefault();
var target = $(this).attr("target");
if(event.keyCode!=='40'){
if (!$(".li-menu").is(":visible") && target===undefined) {
location.href=this.href;
}
else {
window.open(this.href,'_blank');
}
}
});
See the keycode for the reference https://css-tricks.com/snippets/javascript/javascript-keycodes/
in order to configure your app for particular key event
Looking at the classes dropdown-toggle, navbar-collapse, I'm guessing that you are using Bootstrap library.
If that is the case, the behaviour you are seeing is reasonable. Let's break down the issues:
on down arrow keypress , click event is getting fired
Q: You have only bind the handler on click event so why are it is being triggered on keypress?
A: Because this is a feature of bootstrap dropdown. To have better accessibilty, bootstrap triggers click event on the keydown of up, down, esc and space keys.
event.keycode is undefined
Since it is a click event handler and not some keyboard event handler like keydown or keypress, event.keyCode should be undefined
Note: You are using a strict equality in the following condition
if (event.keyCode !== '40')
This will check both the type and value of the operands. Now, event.keyCode always return a Number while '40' is a string, hence the above condtion will yield false even if keyCode is 40. You should correct it to:
if (event.keyCode !== 40)
Now, if you want to stop the redirect on down key, you should check whether the event triggered is an original event or was triggered by some js logic. For this, you may choose jQuery's event.isTrigger or event.originalEvent
Here's a code snippet:
$(".dropdown:not(.li-search) a.dropdown-toggle", ".navbar-collapse").on("click", function(event) {
var target = $(this).attr("target");
// Check if NOT an triggered event
if (!event.isTrigger) {
if (!$(".li-menu").is(":visible") && target === undefined) {
location.href = this.href;
} else {
window.open(this.href, '_blank');
}
}
});
<a> tags will fire the click event when you press enter on them. However you will not have a keyCode on the event because it is not a Key* event. If you want to know the keyCode add a keyDown or keyUp handler as well. You could also handle both by doing something like the following:
$(".dropdown:not(.li-search) a.dropdown-toggle", ".navbar-collapse").on("click keydown", function(event) {
var target = $(this).attr("target");
if(event.type === 'keydown' && event.keyCode!=='40'){
if (!$(".li-menu").is(":visible") && target===undefined) {
location.href=this.href;
}
else {
window.open(this.href,'_blank');
}
}
});
You'll probably also want to add an event.preventDefault(); in there if you wish to prevent default browser behaviour from taking place.

Use a preventdefault to get out of the loop after pressing Enter key

This is a complete revision of my initial question, all unnecessary resources and references were deleted
I am tying the same event listener to 2 different elements: a button and Enter key, and it looks like the following:
var funcelement = function(){
//function code
};
$('#buttonID').click(funcelement);
$('#inputID').keyup(function () {
if (event.which == 13) {
$('#buttonID').trigger('click');
}
})
What I am trying to do is to prevent propagation of the enter key press if focus is on the submit button(#buttonID) by using preventDefault().
So I tried various combinations to make it work. The following is the latest result on my attempts
$('#inputID').keyup(function () {
var hasfocus = $('#buttonID').is(':focus') || false;
if (event.which == 13) {
if (!hasfocus) {
event.preventDefault();
$('#buttonID').trigger('click');
//hasfocus = true;
}
else {
//event.preventDefault();
//$('#buttonID').trigger('click');
}
}
})
After I enter a text into an input box and press Enter key, a confirmation window with yes/cancel buttons pops up with focus on yes button. Once I press Enter again, another window confirming that changes were made pops up with Ok button focused on it. Once I press Enter again, everything I need is being made.
However, there is one problem: after the last step is done, I am going back to the if (!hasfocus) line.
How do I prevent that from happening? Once the stuff I need is done - I don't want to go into that line again.
You can pass a parameter to into the function and stop the propagation there like so:
var funcelement = function(event, wasTriggeredByEnterKey){
if (wasTriggeredByEnterKey && $('#buttonID').is(':focus')) {
event.stopPropagation;
}
//function code
};
$('#buttonID').click(funcelement);
$('#inputID').keyup(function () {
if (event.which == 13) {
$('#buttonID').trigger('click', [true]);
}
}
)
UPDATE
In order to answer your revised issue, you should use the "keydown" event rather than "keyup" when working with alerts. This is because alerts close with the "keydown" event but then you are still triggering the "keyup" event when you release the enter key. Simply change the one word like this:
$('#inputID').keydown(function () {
var hasfocus = $('#buttonID').is(':focus') || false;
if (event.which == 13) {
if (!hasfocus) {
event.preventDefault();
$('#buttonID').trigger('click');
//hasfocus = true;
}
else {
//event.preventDefault();
//$('#buttonID').trigger('click');
}
}
})

Forbidding Apostrophe while typing in HTML textBox

I am looking for a simple maybe JS to forbid apostrophe onKeyUp or OnKeyPress kind of thing. For ex, every time user presses a key if it was apostrophe (Jame's Pizza) replace it with space. I don't want to process it in PHP
I found a code but it ties the JS to the textfield Name which I don't want. I need something global,
It's always better to prevent the keystroke than to retroactively delete it. To accomplish this, you need to intercept the keypress event (keyup is too late):
document.getElementById('yourTextBoxID').onkeypress = function () {
if (event.keyCode === 39) { // apostrophe
// prevent the keypress
return false;
}
};​
http://jsfiddle.net/TSB9r/
If you only want to stop the ' from appearing in the box but would like the keypress event to propagate to parent elements, replace the return false; with event.preventDefault();. (suggested by Eivind Eidheim Elseth in the comments)
Please find below functions. It grabs all of the input elements on the page and assigns keydown and keyup event handlers to each of them. If they detect an apostrophe, it will call the preventDefault() method..
function listen(event, elem, func) {
if (elem.addEventListener) return elem.addEventListener(event, func, false);
else elem.attachEvent('on' + event, func);
}
listen('load', window, function() {
var inputs = document.getElementsByTagName('input');
for (var i = 0; i < inputs.length; i += 1) {
keyHandler(i);
}
function keyHandler(i) {
listen('keydown', inputs[i], function(e) {
if (e.keyCode === 222) { // 222 is the keyCode for apostrophe
e.preventDefault();
}
});
listen('keyup', inputs[i], function(e) {
if (e.keyCode === 222) { // 222 is the keyCode for apostrophe
e.preventDefault();
}
});
}
});

Categories

Resources