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Javascript events in Chrome and Firefox

I noticed that these function doesn't work good in Firefox, but does in Chrome.
I use these function in a game in Js to shoot bullet (left mouse click) and to create a fireball all around the player with the right click that burns everyone in a small radius.
document.onclick = function(event) {
if(!player){ //to avoid onclick to be used before calling Player();
return;
}
if(player.canAttack && player.distance >= 80) { //not for sword attack
performAttack(player);
player.canAttack = false;
}
if(player.distance < 80)
performAttack(player);
//event.preventDefault();
}
document.oncontextmenu = function(event) {
//hide default behaviour of right click -> no context menu popup
event.preventDefault();
if(player.obtainedGadjet > 0) {
player.pressingMouseRight = true;
performSpecialAttack(player);
}
}
In the performAttack function I set player.isStopped = true, so my updatePlayer() doesn't change player.x and player.y while he's attacking. The same for the fireball attack. I want my player stays there.
It works in chrome, my player stops, attacks,and then can moves again, but in Firefox if I right click it somethimes acts instead as I have left clicked, so shoot the magic ball, and maybe then the fireball too. Furthermore, my player ignore isStopped = true, it seems like in Firefox oncontextmenu has "lower priority" than other events.
Any idea?
Thanks

Please note that a click event contains information about which button was pressed. You can try yourself with something like:
document.addEventListener('click', function(ev){
console.log(ev.button);
});
And, yes, click events are fired when you right-click, even if you're doing something on related contextmenu events.
So your code should look a bit more like
document.addEventListener('click', function(ev){
if (ev.button === 0) {
// Perform primary action
} else if (ev.button === 2) {
// Perform secondary action
}
});
document.addEventListener('contextmenu', function(ev){
ev.preventDefault();
});

Using the same click event is advisable as said by Ivan. You may also want to read this other discussion here on SO about best practices and why it's not always good to disable default right click behaviour (i.e.: it's not always guaranteed to work).

Disable Mouse-wheel to scroll up or down

I have two pages, these are the conditions I cannot achieve, please let me know if it is not possible.
In one page, I need to disable the mouse-wheel to scroll up. So when I scroll up with mouse-wheel nothing happens, but when I scroll down the page scrolls.
In the other page, I want the exact opposite, I need to disable the scrolling down on mouse-wheel. So when I scroll down nothing happens, but when I scroll up the page scrolls.
This is all i really need, but if you think I need to explain more, please let me know, thank you.

This code works for div with id "mydiv". You can change the mydiv to the body or any other element you want. The code works in all browsers.
JS:
var mydiv = document.getElementById("mydiv");
if (mydiv.addEventListener) {
// IE9, Chrome, Safari, Opera
mydiv.addEventListener("mousewheel", MouseWheelHandler, false);
// Firefox
mydiv.addEventListener("DOMMouseScroll", MouseWheelHandler, false);
}
// IE 6/7/8
else
mydiv.attachEvent("onmousewheel", MouseWheelHandler);
function MouseWheelHandler(e) {
// cross-browser wheel delta
var e = window.event || e; // old IE support
var delta = Math.max(-1, Math.min(1, (e.wheelDelta || -e.detail)));
if(delta==1) // if mouse scrolls up
{
alert('up');
}
if(delta==-1) // if mouse scrolls down, we disable scrolling.
{
e.preventDefault();
e.stopPropagation();
return false;
}
return false;
}
NOTE: Remember to set overflow to auto or scroll for this function to work.
A working example: Click Here
Hope this helps.

Case of preventing mouse scroll down (for mouse scroll up just change comparison operator to '<'):
$(window).on("wheel mousewheel", function(e){
if(e.originalEvent.deltaY > 0) {
e.preventDefault();
return;
} else if (e.originalEvent.wheelDeltaY < 0) {
e.preventDefault();
return;
}
});
We need to check for two values because of cross-browser issues.
jsFiddle link
P. S. Warning. Since later versions of Chrome decides to treat all window events as passive by default, the code above won't work in Chrome. Will come with a better solution and update this answer ASAP.

You could try this to disable mouse scroll. I understand this is not as per your question but I believe it could help you.
JS:
function disableMouseScroll() {
return false;
}
document.onmousewheel=disableMouseScroll;
Link

Touch Screen Preventing Scroll

I have a Lenovo touch screen desktop where I am running a touch based website. The problem is that browsers (Chrome) seem to freeze when I click with eight fingers and try to scroll around. The browser locks up. So I'm attempting to create a function with jQuery that will only register one single touch event.
Here is what I have now:
var isTouched = false;
var $document = $(document);
$document.on('touchstart', function (e) {
if (!isTouched) {
isTouched = true;
console.log('start: ' + isTouched);
$document.on('touchend', function() {
if (isTouched) {
isTouched = false;
console.log('end: ' + isTouched);
}
});
}
});
Which works ok, but it prevents me from scrolling, and the touchend seems to be firing when I lift the first finger off the screen. The expected behavior would be for touchend only to fire when I lift the finger off the screen that caused the touchstart. Any suggestions for creating a function which will only register one touchstart at a time and allow scrolling (i.e. not ignore the touchmove).

Prevent page scroll on drag in IOS and Android

I'm working on a html5 canvas game, but I don't know how to handle touch events. When a user touch the screen, and drag, then the browser will scroll the page. I would like to prevent it, and get the touch start, and touch end position. Is it possible?
Thanks in advance

You need to override the default touch behaviour to stop touchevents dragging the page. Clearly, you'll need to handle them again if your page becomes larger than the available area, but as you're making a game, going to assume you're doing 100%/100% layout.
function preventBehavior(e) {
e.preventDefault();
};
document.addEventListener("touchmove", preventBehavior, {passive: false});
Edit: here's the W3C recommendation talking about touch events, which might be handy for you.

Due to breaking changes made in recent versions of Chrome, the above answers are no longer correct. Attaching a touch event listener to the document or body elements will cause the event listener to be registered in "passive" mode, which causes calls to preventDefault to be ignored.
There are two solutions:
The preferred solution is to use the CSS style touch-action to specify that no scrolling should happen (e.g. with the value "none")
In cases where this is not appropriate (e.g. if the type of interaction should change dynamically in a way that cannot be determined before the gesture begins) then the event listener must be registered with the third parameter set to { passive: false } (you should perform browser detection to ensure that this style is supported first, though).

If you don't want to use jQuery mobile or any other library then you can try this.
var startX, startY, endX, endY;
document.addEventListener("touchstart", function(e){
startX = e.touches[0].pageX;
startY = e.touches[0].pageY;
e.preventDefault();//Stops the default behavior
}, false);
document.addEventListener("touchend", function(e){
endX = e.touches[0].pageX;
endY = e.touches[0].pageY;
e.preventDefault();//Stops the default behavior
}, false);

canvas.addEventListener('touchstart', function(e)
{
alert(e.changedTouches[0].pageX + " " + e.changedTouches[0].pageY);
}
canvas.addEventListener('touchend', function(e)
{
alert(e.changedTouches[0].pageX + " " + e.changedTouches[0].pageY);
}
Here's a good article about touching and gesturing on mobile phones:
http://www.sitepen.com/blog/2008/07/10/touching-and-gesturing-on-the-iphone/

Following solution preventing scroll when dragging AND at the same time usual scroll is working (when not dragging)
var scrollable = true;
var listener = function(e) {
if (! scrollable) {
e.preventDefault();
}
}
document.addEventListener('touchmove', listener, { passive:false });
onDragstartHandler() {
scrollable = false;
}
onDragendHandler(} {
scrollable = true;
}
Don't forget to bind onDragstartHandler and onDragendHandler to related elements

Safari iPad 1: how to disable zoom/centering on double-tap, but keep pinch zoom

I wonder if its possible to prevent double-tap-to-zoom and double-tap-to-center on a specific HTML element in Safari iOS (iPad 1) ?
Because my small HTML5 game forces users to make fast clicks (or taps), which are interpreted as double clicks, and when it happens - the page changes zoom and centers itself.
Detecting double clicks (like in this answer - Safari iPad : prevent zoom on double-tap) smells bad..
Wrong answer #1:
<meta name="viewport" content="width=device-width, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no"> - does not suit my purposes, because it will block any zoom.
Wrong answer #2: maybe would .preventDefault() on click event alone be enough for that ? - Does not have any effect.

There's no other way than catching the events you want to prevent, and call preventDefault() on them, as you had already more or less figured out.
Indeed, some particular CSS properties / values may change the global site behavior (fixed width or fixed, for example), but you're not safe from changes to the OS (see fixedhandling change in iOS5), nor do these changes necessarily prevent all behavior (pinch might be off, but not double-tapping).
So, the best way to disable default behavior only for double-tapping is to take advantage of the count of touches iOS provides: if we have only one contact, then we're tapping. Two, this means we're pinching.
The following setup code provides that functionality:
var elm = document.body; // or some selection of the element you want to disable
var catcher = function(evt) {
if (evt.touches.length < 2)
evt.preventDefault();
};
elm.addEventListener('touchstart', catcher, true);
Demo on jsFiddle.
Note: the third parameter (true) to addEventListener means that we want to capture events, that is catch them all, even for our descendant children.

I am preventing doubletaps like this:
var doubleTouchStartTimestamp = 0;
$(document).bind("touchstart", function (event) {
var now = +(new Date());
if (doubleTouchStartTimestamp + 500 > now) {
event.preventDefault();
}
doubleTouchStartTimestamp = now;
});
The elegance lies within the fact, that no timeouts are needed. I only update a timestamp. It only gets compared on the next touchstart. Works for me on iOS 6.
Doubletaps further down the dom are not affected.
The same works without jQuery, as well:
var doubleTouchStartTimestamp = 0;
document.addEventListener("touchstart", function (event) {
var now = +(new Date());
if (doubleTouchStartTimestamp + 500 > now) {
event.preventDefault();
}
doubleTouchStartTimestamp = now;
});

I wrote a jQuery plugin for the same purpose - selectively disabling double-tap zoom on given page elements (in my case, navigation buttons to flip pages) I want to respond to every tap (including double-tap) as a normal click event, with no iOS "touch magic", no matter how fast the user clicks it.
To use it, just run something like $('.prev,.next').nodoubletapzoom(); on the elements you care for. The principle it uses is to listen for consecutive touchstart events on a node within 500ms, and running event.preventDefault() on the second, unless other touches are active at the same time. As that preventDefault consumes both touches, we also synthesize the two "missed" click events for the node, so your intended touch action happens as many times as the user intended.

Apple has a lot of tips with specialized tags for webkit (Safari). View Official Docs

What iOS version/Safari browser are you using? That site most definitely does not let you double-tap. I found some CSS but haven't had time to try it as I'm about to step out:
body {
-webkit-text-size-adjust:none;
margin:0px;
}
div{
clear:both!important;
display:block!important;
width:100%!important;
float:none!important;
margin:0!important;
padding:0!important;
}

You will need to implement a double tap function and preventDefault on the second tap. Here is some tested code that uses global variables that should get you started:
<button id="test1">Double Tap Me!</button>
<div id="test2">EMPTY</div>
var elm1 = document.getElementById('test1');
var elm2 = document.getElementById('test2');
var timeout;
var lastTap = 0;
elm1.addEventListener('touchend', function(event) {
var currentTime = new Date().getTime();
var tapLength = currentTime - lastTap;
clearTimeout(timeout);
if (tapLength < 500 && tapLength > 0) {
elm2.innerHTML = 'Double Tap';
event.preventDefault();
} else {
elm2.innerHTML = 'Single Tap';
timeout = setTimeout(function() {
elm2.innerHTML = 'Single Tap (timeout)';
clearTimeout(timeout);
}, 500);
}
lastTap = currentTime;
});
And a fiddle: http://jsfiddle.net/brettwp/J4djY/

JQuery approach to disable Double Tap Zoom in MVC4
To Disable the double tap (double mouse down) functionality on iOS 1+ you need to catch the touchStart Event and create an override to prevent the zoom.
// Using Single script.js and JQuery.Mobile-1.2.0 UI each page in MVC gets assigned JQuery through delegates so you don't have to do a full refresh of the page allowing you to take advantage of the data-prefetch which loads the page in the DOM when the app loads for the first time
$(document).delegate("#CashRegister", "pageinit", function () {
// To Disable 'Pinch to Zoom' Note: don't implement gester event handlers if you want to
//keep pinch to zoom functionality NOTE: i use this as my pageinit is a delegate of a page
this.addEventListener("gesturestart", gestureStart, false);
this.addEventListener("gesturechange", gestureChange, false);
this.addEventListener("gestureend", gestureEnd, false);
//handle each event by disabling the defaults
function gestureStart(event) {
event.preventDefault();
}
function gestureChange(event) {
event.preventDefault();
}
function gestureEnd(event) {
event.preventDefault();
}
//Recreate Double Tap and preventDefault on it
$(this).bind('touchstart', function preventZoom(e) {
// recreate the double tab functionality
var t2 = e.timeStamp
, t1 = $(this).data('lastTouch') || t2
, dt = t2 - t1
, fingers = e.originalEvent.touches.length;
$(this).data('lastTouch', t2);
if (!dt || dt > 500 || fingers > 1) return; // not double-tap
e.preventDefault(); // double tap - prevent the zoom
// also synthesize click events we just swallowed up
$(this).trigger('click').trigger('click');
});

Actually, .preventDefault() definitely does work... using jQuery:
var InputHandler = {
startEventType : isTouch ? "touchstart" : "mousedown"
}
$(selector).bind(InputHandler.startEventType, function(evnt) {
evnt.preventDefault();
});
Your problem with trying to prevent on .click() is that the browser isn't throwing a "click" element. Safari only fires a click to help simulate a click... But when there's a double tab, Safair doesn't through a "click" element. Your event handler for .click() doesn't ever fire, and therefore the .preventDefault() doesn't fire either.