I'm currently running into an issue with trying to use the JavaScript event object. I have a Javascript function that waits for an onblur event and check to see if a the shiftkey is being pressed for an element on the document and do something if that's the case. The event.shiftKey works perfectly in IE 9 to detect if the shift key is pressed, but for the event object is different for an onblur event in IE 11 and it doesn't support the shiftKey event. When I did an alert on the event object, it says it was '[ojbect msEventObj]' in IE 9 and '[object focusEvent]' in IE 11. Is there a way to get around this difference between IE 9 and IE 11?
Here's the JavaScript code:
//using alert(event.shiftkey) gives me undefined in IE 11 because event
//is focusEvent object not msEventObj for some reason
element.onblur = function (){
if (event.shiftKey == false) {
alert('shift key was not pressed!');
}
}
The problem is that event.shiftKey is not accessible from onblur - and you weren't passing the event to your event handler - I think you're trying to target onkeypress:
element.onkeypress = function (ex) { //pass event to handler ('ex' in this example)
alert(ex.shiftKey);
}
This returns true when the shift key is being held down - false when it is not.
you didn't define event, should be like this:
element.onblur = function (event){
if (event.shiftKey == false) {
alert('shift key was not pressed!');
}
}
I came across a similar problem for tab navigation.
element.addEventListener('keydown', (event) => {
if (event.keyCode !== 9) return;
if (!event.shiftKey) {
event.preventDefault();
YOURTARGET.focus();
}
});
Instead of a blur event, I listen for a keydown, check if it's tab, then run the code I want. It gives me access to event.shiftKey.
I'm having trouble with e.preventDefault() for IE(8).
Everything works in Chrome (meaning the execution is correct, and the default action is prevented). However, in IE, the execution is correct but the default action happens as well.
In further investigation I found that whenever I look at the event object, it fails (no error, just exits the handler quietly).
I removed all the code and boiled it down as follows:
google.earth.addEventListener(spot.placemark, 'click', test);
function test(e){
alert(1);
e.returnValue = false;
alert(2);
if(e.preventDefault) e.preventDefault();
alert(3);
return(false);
}
So with IE, only the first alert fires. With chrome they all fire. If I reverse alert 2 and alert 3, still only alert 1 fires. Fundamentally - touching e fails.
I also tried using the window.event object instead of relying on the passed value of e.
var e = window.event;
But that had the same effect. Appreciate some pointers. Thank you
as answered in event.preventDefault() function not working in IE
function test(e) {
e.preventDefault ? e.preventDefault() : e.returnValue = false;
}
How do I consume a key event in javascript, so that it doesn't propagate?
If you don't want the event to propagate and you're not using jQuery (or another library that wraps native browser events), you need to use the event's stopPropagation() method in most browsers and its cancelBubble property in IE. Don't bother with return false or preventDefault(): those only affect whether the native browser action happens for the event and have nothing to do with propagation.
For example:
document.onkeypress = function(evt) {
evt = evt || window.event;
if (typeof evt.stopPropagation != "undefined") {
evt.stopPropagation();
} else {
evt.cancelBubble = true;
}
};
Try preventDefault and/or stopPropagation.
My code works fine in FF/Chrome/Everything except IE(failed in both 7/8, didn't bother going furthur down). Due to restrictions, I cannot use jQuery and am hard-coding the Javascript. The issue is with IE, I am getting "preventDefault is null or not an object". Hoping one of you has the answer, and here's relevant code:
AddEvent Method:
function addEvent( obj, type, fn ) {
if ( obj.attachEvent ) {
obj['e'+type+fn] = fn;
obj[type+fn] = function(){obj['e'+type+fn]( window.event );}
obj.attachEvent( 'on'+type, obj[type+fn] );
} else
obj.addEventListener( type, fn, false );
};
Event handler throwing error:
function mousedown(e){
if(e.preventDefault){
e.preventDefault();
} else {
e.returnValue = false;
e.cancelBubble=true;
}
//Processing
};
Also DOCTYPE and charset are both set on the calling HTML page. Any ideas would be appreciated. The error is thrown in the if statement for the mousedown method.
EDIT:
Due to the fact that grabbing window.event did "fix" the main issue, I discovered the problem was a different section of code. Basically I am adding a element ontop of a pre-placed element, and then registering mousedown/mousemove events to that div. When firing the event on the <div>, THAT'S where the error is thrown.
Could this be something due to the fact that I have events registered to 2
rect = document.createElement('div');
rect.className='square';
rect.id='chooser_rectangle';
rect.style.left=initx+'px';
rect.style.top=inity+'px';
addEvent(rect,"mousemove",mousemove);
addEvent(rect,"mousedown",mousedown);
In IE the event object is not passed as the first argument to an event handler. Instead it is a global variable:
function mousedown(e){
var evt = e || window.event; // IE compatibility
if(evt.preventDefault){
evt.preventDefault();
}else{
evt.returnValue = false;
evt.cancelBubble=true;
}
//Processing
};
IE has a different event model to other browsers (even IE8). In IE you would call this to do the same thing:
event.returnValue = false;
You need to determine what the browser supports and call the correct method. So first check if event.returnValue is set, if so then call it, otherwise call preventDefault().
Following is my JavaScript (mootools) code:
$('orderNowForm').addEvent('submit', function (event) {
event.preventDefault();
allFilled = false;
$$(".required").each(function (inp) {
if (inp.getValue() != '') {
allFilled = true;
}
});
if (!allFilled) {
$$(".errormsg").setStyle('display', '');
return;
} else {
$$('.defaultText').each(function (input) {
if (input.getValue() == input.getAttribute('title')) {
input.setAttribute('value', '');
}
});
}
this.send({
onSuccess: function () {
$('page_1_table').setStyle('display', 'none');
$('page_2_table').setStyle('display', 'none');
$('page_3_table').setStyle('display', '');
}
});
});
In all browsers except IE, this works fine. But in IE, this causes an error. I have IE8 so while using its JavaScript debugger, I found out that the event object does not have a preventDefault method which is causing the error and so the form is getting submitted. The method is supported in case of Firefox (which I found out using Firebug).
Any Help?
in IE, you can use
event.returnValue = false;
to achieve the same result.
And in order not to get an error, you can test for the existence of preventDefault:
if(event.preventDefault) event.preventDefault();
You can combine the two with:
event.preventDefault ? event.preventDefault() : (event.returnValue = false);
If you bind the event through mootools' addEvent function your event handler will get a fixed (augmented) event passed as the parameter. It will always contain the preventDefault() method.
Try out this fiddle to see the difference in event binding.
http://jsfiddle.net/pFqrY/8/
// preventDefault always works
$("mootoolsbutton").addEvent('click', function(event) {
alert(typeof(event.preventDefault));
});
// preventDefault missing in IE
<button
id="htmlbutton"
onclick="alert(typeof(event.preventDefault));">
button</button>
For all jQuery users out there you can fix an event when needed. Say that you used HTML onclick=".." and get a IE specific event that lacks preventDefault(), just use this code to get it.
e = $.event.fix(e);
After that e.preventDefault(); works fine.
I know this is quite an old post but I just spent some time trying to make this work in IE8.
It appears that there are some differences in IE8 versions because solutions posted here and in other threads didn't work for me.
Let's say that we have this code:
$('a').on('click', function(event) {
event.preventDefault ? event.preventDefault() : event.returnValue = false;
});
In my IE8 preventDefault() method exists because of jQuery, but is not working (probably because of the point below), so this will fail.
Even if I set returnValue property directly to false:
$('a').on('click', function(event) {
event.returnValue = false;
event.preventDefault();
});
This also won't work, because I just set some property of jQuery custom event object.
Only solution that works for me is to set property returnValue of global variable event like this:
$('a').on('click', function(event) {
if (window.event) {
window.event.returnValue = false;
}
event.preventDefault();
});
Just to make it easier for someone who will try to convince IE8 to work. I hope that IE8 will die horribly in painful death soon.
UPDATE:
As sv_in points out, you could use event.originalEvent to get original event object and set returnValue property in the original one. But I haven't tested it in my IE8 yet.
Mootools redefines preventDefault in Event objects. So your code should work fine on every browser. If it doesn't, then there's a problem with ie8 support in mootools.
Did you test your code on ie6 and/or ie7?
The doc says
Every event added with addEvent gets the mootools method automatically, without the need to manually instance it.
but in case it doesn't, you might want to try
new Event(event).preventDefault();
if (e.preventDefault) {
e.preventDefault();
} else {
e.returnValue = false;
}
Tested on IE 9 and Chrome.
To disable a keyboard key after IE9, use : e.preventDefault();
To disable a regular keyboard key under IE7/8, use : e.returnValue = false; or return false;
If you try to disable a keyboard shortcut (with Ctrl, like Ctrl+F) you need to add those lines :
try {
e.keyCode = 0;
}catch (e) {}
Here is a full example for IE7/8 only :
document.attachEvent("onkeydown", function () {
var e = window.event;
//Ctrl+F or F3
if (e.keyCode === 114 || (e.ctrlKey && e.keyCode === 70)) {
//Prevent for Ctrl+...
try {
e.keyCode = 0;
}catch (e) {}
//prevent default (could also use e.returnValue = false;)
return false;
}
});
Reference : How to disable keyboard shortcuts in IE7 / IE8
Here's a function I've been testing with jquery 1.3.2 and 09-18-2009's nightly build. Let me know your results with it. Everything executes fine on this end in Safari, FF, Opera on OSX. It is exclusively for fixing a problematic IE8 bug, and may have unintended results:
function ie8SafePreventEvent(e) {
if (e.preventDefault) {
e.preventDefault()
} else {
e.stop()
};
e.returnValue = false;
e.stopPropagation();
}
Usage:
$('a').click(function (e) {
// Execute code here
ie8SafePreventEvent(e);
return false;
})
preventDefault is a widespread standard; using an adhoc every time you want to be compliant with old IE versions is cumbersome, better to use a polyfill:
if (typeof Event.prototype.preventDefault === 'undefined') {
Event.prototype.preventDefault = function (e, callback) {
this.returnValue = false;
};
}
This will modify the prototype of the Event and add this function, a great feature of javascript/DOM in general. Now you can use e.preventDefault with no problem.
return false in your listener should work in all browsers.
$('orderNowForm').addEvent('submit', function () {
// your code
return false;
}
FWIW, in case anyone revisits this question later, you might also check what you are handing to your onKeyPress handler function.
I ran into this error when I mistakenly passed onKeyPress(this) instead of onKeyPress(event).
Just something else to check.
I was helped by a method with a function check. This method works in IE8
if(typeof e.preventDefault == 'function'){
e.preventDefault();
} else {
e.returnValue = false;
}