How to Stop Bubbling on DOMSubtreeModified Event? - javascript

I have a pretty simple scenario. I have the following HTML:
<h1>Hello</h1>
<input type="button" value="Change" id="change" />
With the corresponding JS:
var h1 = $("h1").get(0);
h1.addEventListener("DOMSubtreeModified", function(ev) {
console.log("Changed");
ev.bubbles = false;
ev.cancelBubble = true;
ev.defaultPrevented = true;
ev.preventDefault();
ev.stopPropagation();
ev.returnValue = false;
return false;
}, false);
$("#change").click(function() {
$("h1").text("World");
});
So, this basically just changes the text of the H1 node and the event is then fired. However, the event is firing twice (as I assume as a result of bubbling). As you can see, I've tried throwing everything at it to try to get it to not fire twice, but that does not stop it. If you want to play with the code, you can check it out at: http://jsfiddle.net/sECtq/. Any help would be appreciated.

This behaviour is not caused by bubbling.
$.text() executes 2 steps to set the new text:
remove the existing contents
insert a new textNode
Both steps trigger DOMSubtreeModified, so you get 2 alerts.
You may use e.g. the following:
$("h1")[0].firstChild.data="World";
This will only change the contents of the textNode without removing a node.

or you can also check whether propagation has been stopped or not. Take a look on the http://api.jquery.com/event.isPropagationStopped l

Related

Detecting the event that causes focus of HTML span tag

I need to determine the event that causes the focus of an HTML span tag. The span tag is a glyhpicon from bootstrap v3.
Right now, I have a .focus() event handler attached to the span tag to catch when the focus occurs but I can't figure out how to tell if the focus was caused by a click or a tab.
HTML tag: <span class="glyphicon glyphicon-ok-circle col-xs-6"></span>
Jquery:
$("span").focus(function (e) {
var event = "click" //This "event" var is the event that caused the focus
if(event == "click"){
//do something
}else{
//if not a click event, do something else
}
});
Do I use the eventData(e) parameter to detect this?
So far, I haven't been able to find the property that shows what caused the focus inside the eventData(e) parameter. The "originalEvent" property only returns "focus" and not what caused it.
Edit: The answer in Differentiate between focus event triggered by keyboard/mouse doesn't fulfill my question. That user is trying to find whether a click or keyboard event occurs on a jquery "autocomplete" element. I need to find the event that causes the focus on a span tag... not an input tag. The ".focus()" event of the element occurs before all other events.
Answer: Check my post below.
$('span').on('focus', function(e){
$( 'span' ).mousedown(function() {
alert( "focus using click" );
});
$(window).keyup(function (e) {
var code = (e.keyCode ? e.keyCode : e.which);
if (code == 9) {
// Using tab
}
});
});
I appreciate everyone's feedback! The answer suggested in the comments helped to partially solve the problem. However, I can't give full credit because it didn't fully answer the question.
The answer suggested in the link was to create a "click" and "keypress" event to update a flag that would be checked on the ".focus()" event to determine the source of how it was triggered. My scenario was more complex. The ".focus()" event occurs before a "click()" event... so the flags wouldn't trigger until after the focus has already occurred and passed. The answer also suggested using a "setTimeout()" to make the focus event wait.. which I found unnecessary in my conclusion.
Conclusion
After some research, it was apparent that a ".mousedown()" event occurs before the ".focus()" event. Using the binded flags listed in the suggested answer above, I created the code below to solve my problem.
$(document).bind('mousedown', function () { isClick = true; }).bind('keypress', function () { isClick = false; });
$("span").focus(function () {
if (isClick) {
//Focused by click event
} else{
//Focused by keyboard event
}
});
I also noticed during research that ".bind()" has been deprecated in Jquery v3.0... so I will be switching my code to read:
$(document).mousedown(function () { isClick = true; }).keypress(function () { isClick = false; });
$("span").focus(function () {
if (isClick) {
//Focused by click event
} else{
//Focused by keyboard event
}
});
Please add any comments/suggestions/optimizations as a comment to my answer! Would love to hear other input.

jQuery preventDefault() doesn't work like I expect - is this a jQuery Bug?

This is simplified code to exactly reproduce a problem I'm having with jQuery.
I would expect it to cancel the original click, then trigger the click event again which in turn would cause the browser to load the href of the url.
<script type="text/javascript">
$( function()
{
var confirmed = false;
$('a').click( function( event )
{
if ( confirmed == false )
{
event.preventDefault();
confirmed = true;
$(event.target).trigger( 'click' );
}
});
});
</script>
Original Question Here
I do not want to change window.location. I want to trigger so that any event handlers that have been bound to the click event will fire too. It just so happens that I also want the browser to follow the link.
.trigger('click') won’t trigger the browser’s default action — it will just trigger jQuery event handlers bound to that event on that element.
Take a look at this answer — you need to create and fire a click event yourself. Here’s the code from that answer:
function fireEvent(obj,evt){
var fireOnThis = obj;
if( document.createEvent ) {
var evObj = document.createEvent('MouseEvents');
evObj.initEvent( evt, true, false );
fireOnThis.dispatchEvent( evObj );
} else if( document.createEventObject ) {
var evObj = document.createEventObject();
fireOnThis.fireEvent( 'on' + evt, evObj );
}
}
Your event handler will always be run when you trigger a "click" event, and before the default behavior happens. So no, it's not a bug.
edit — If you want the default action to happen when the element is clicked and your various conditions are satisfied, just return from your handler.
$('a').click( function( event )
{
if ( confirmed == false )
{
event.preventDefault();
confirmed = true;
}
else
return;
});
When your handler returns, the browser will carry on with the default behavior.
edit again — and of course if you want to simply carry out programmatically the default action of an <a> tag with an "href" attribute, it's just:
window.location = $(element).attr('href');
No need for a "click" event at all.
preventDefault() doesn't cancel the jquery bound click action; it cancels the 'default' click action that is inherent to an anchor tag. unbind() is the proper function for canceling any action/function that is bound to an object.
It looks like you have one state where you want to inhibit the default action (and update a flag), and another state where you simply want the default action to apply. Wouldn't removing the else case entirely do the trick? With no preventDefault() the default click action will still run.
Edit: Pointy's answer now shows your code updated similarly.
Edit: I'm still not entirely sure what you're going for, but if for some reason you must trigger manually, one way to prevent a stack overflow due to recursion would be to assign a custom event (i.e., not click), and then always suppress the default action. Then in your conditional, either do or don't fire the custom event.
So, something like this (untested):
$('a')
.bind('fancyclick', function () { // Your special click logic
changeStatusOf( confirmed );
doCrazyStuff();
location.replace( $(this).attr('href') ); // or whatever
})
.click( function (e) {
e.preventDefault(); // Always suppress natural click
if ( confirmed ){
$(this).trigger('fancyclick'); // Fire the special click
}
});
I'll simply write while I analyse, hoping it'll be easy to follow and easy to compare to your code. Kick me when I can optimize/enhance my replies in any way.
checking - part 1
Move the "preventDefault" outside of the "if" statement! If you don't move it outside of the "if", the code will skip the "preventDefault" if confirmed == true.
<script type="text/javascript">
$( function()
{
var confirmed = false;
$('a').click( function( event )
{
event.preventDefault();
if ( confirmed == false )
{
confirmed = true;
$(event.target).trigger( 'click' );
}
});
});
</script>
checking - part 2
Besides that, I'm wondering about the existence of "var confirmed" in general. The code would also work flawless without it since you're not using the confirmed variable in the function anywhere else...
<script type="text/javascript">
$( function()
{
$('a').click( function( event )
{
event.preventDefault();
$(event.target).trigger( 'click' );
});
});
</script>
checking - part 3
Knowing you can replace the trigger with a simple click, did you try that?
<script type="text/javascript">
$( function()
{
$('a').click( function( event )
{
event.preventDefault();
$(event.target).click();
});
});
</script>
checking - part 4
If the click still fails on the target element, it's definitely time to inspect (using "FireBug on Firefox" or alike) if "event.target" holds an object at all. You never know...
checking - part 5
One more thing: I don't see any Document Ready checking, so I hope you've put that script at the end of your file, right before the "</body>" tag. If you load it in the "<head>" without checking Document Ready, it might happen that javascript tries to bind the event to an element that is yet to be loaded into the dom... which would be like throwing feathers against a 9 Inch steel plate... nothing will happen. ;)
that's all
That's all that comes to mind as an answer to your question. One of them could fix the issue you're having. At least, that's what I hope. These little snippets here at stackoverflow leave massive probabilities related to what we don't see. It's hard to be sure what might be missing when you don't have the "complete view". ;)
How about doing something like creating a link offscreen that would handle the final click? That way, you can prevent the click of the original link, handle the code, then proceed to trigger the click of the hidden copy.

Checkbox inside an anchor click behavior

Consider following snippet:
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.6.2/jquery.min.js"></script>
</head>
<body>
<form>
<a id="a" href="http://google.com">Goooooogle</a>
</form>
<script>
$(function() {
var checkbox = $('<input type="checkbox"></input>');
checkbox.prependTo($('#a'));
checkbox.click(function(e) {
e.stopPropagation();
// do something useful
});
});
</script>
</body>
</html>
I want to get a checkbox inside <a>, and get following on-click behavior:
Toggle check mark normally as usual
Do something useful like AJAX-request
Stay on this page, i.e. not be redirected to an a href
Also I want to not override default behavior if I click anywhere in a, but not on checkbox. I.e. I want to allow to execute all event handlers associated with a click itself.
I thought that should be pretty easy, but I can't get desired behavior. Either:
I get redirected to Google if I put a code provided.
I don't get check mark toggled if I use e.preventDefault() of return false;. Furthermore in that case checkbox ignores explicit checkbox.attr('checked', 'checked') and all other possible ways to set the check mark.
Where is the catch?
UPD: This works as expected in Chrome, e.g. I'm not redirected on click, but fails in Firefox. Is there cross-browser way?
Well, it looks like a known Firefox bug, which leads to following link on checkbox click regardless of handlers' code. As a bit dirty workaround one can use:
var checkbox = $('<input type="checkbox"></input>');
checkbox.prependTo($('#a'));
checkbox.click(function(e) {
setTimeout(function() { checkbox.prop('checked', !checkbox.prop('checked')); }, 10);
// do something useful on clicking checkbox and but not surrounding link
return false;
});
I know this is an old question but some may still be curious since it was never really fully answered without a messy hack or workaround. All you have to do is simply check where the event's target originated.
So using your example (jsfiddle):
// Don't change pages if the user is just changing the checkbox
$("#a").click(function(e) {
//e.preventDefault(); // Optional if you want to to keep the link from working normally
alert("Click came from: " + e.target.tagName);
if (e.target.tagName != "INPUT") {
// do link
alert("Doing link functionality");
} else {
// do something useful
alert("Doing checkbox functionality");
}
});
I Know this question is over 5 years old, but I had the same issue recently and the work-around I found was to add an onclick function to the checkbox and in that function call event.stopImmediatePropagation().
from w3schools: "The stopImmediatePropagation() method prevents other listeners of the same event from being called"
ie...the anchor.
function checkbox_onclick(event){
event.stopImmediatePropagation();
}
here's a modified script
var checkbox = $('<input type="checkbox"></input>');
var a = $('#a');
a.unbind("click").click(function(e) {
e.preventDefault();
checkbox.attr('checked', !checkbox.attr('checked'));
});
checkbox.prependTo(a);
checkbox.click(function(e) {
e.stopPropagation();
// do something useful
});
i unbind the click event on the <a> and rebind it with a event to check/uncheck the checkbox and also prevent the default.

Call a function after form reset

Is there a method for me to call a function after click on the reset button in form, and I mean after, so that the form is first reset and then my function called. Normal event bubbling would call my function and only then reset the form. Now I would like to avoid setTimeout in order to do this.
What I need is to call a function when a form is reset because I use uniform and uniform needs to be updated when values change.
At the moment I do it like this:
//Reset inputs in a form when reset button is hit
$("button[type='reset']").live('click', function(){
elem = this;
//Sadly we need to use setTimeout to execute this after the reset has taken place
setTimeout(function(){
$.each($(elem).parents('form').find(":input"), function(){
$.uniform.update($(this));
});
}, 50);
});
I tried to do al this on $(':input').change() but reseting an element does not seem to trigger the change event.
Thank you in advance for any help.
HTML forms do have an onReset event, you can add your call inside there:
function updateForm()
{
$.each($('form').find(":input"), function(){
$.uniform.update($(this));
});
}
<form onReset="updateForm();">
As pointed out in the comment by Frédéric Hamidi you can also use bind like so:
$('form').bind('reset', function() {
$.each($(this).find(":input"), function(){
$.uniform.update($(this));
});
});
After some testing it appears both ways fire before the reset takes place and not after. The way your doing it now appears to be the best way.
The same conclusion was found in this question here
I haven't yet tested in all browsers, but you can do your own ordering within a click event:
http://jsfiddle.net/vol7ron/9KCNL/1/
$(document).ready(function() {
$("input:reset").click(function() { // apply to reset button's click event
this.form.reset(); // reset the form
window.alert($("input:text").val()); // call your function after the reset
return false; // prevent reset button from resetting again
});
});
Time ago I worked debugging a Google IE related plugin and I solved the main error with a bubbling trick. That's why I think immediately in this solution for your problem (of course should be cross-browser):
<form>
<div id="capture_bubble">
<input type="text"><input type="reset">
</div>
</form>
In this way you can capture the bubbling with $('#capture_bubble') after reset event be triggered.
You can make a quick test with:
(function($) {
$(function() {
$('#capture_bubble').live('click', function(){
console.debug('capture_bubble');
alert('capture_bubble')
})
$("input[type='reset']").live('click', function(){
this.form.reset(); // forcing reset event
console.debug('reset');
alert('reset')
});
});
})(jQuery);
Please note: this.form.reset(); (change made due to a jeff-wilbert observation)
you shouldn't need to wait 50 milliseconds. If you use setTimeout with a timeout of zero, it effectively means "push this code onto the event stack". Since the form-reset is guaranteed to have fired first, the code in the setTimeout is guaranteed (in well behaved javascript interpreters) to have access to the form values you want (post-reset). You should be able to use the code below, guilt-free.
var afterReset = function(){
var pushMeOntoTheEventStack = window.setTimeout(function(){
$("#form input").each(function(){
console.log( this.name + ' = ' + this.value );
});
},0);
};
$("#form").on("reset",afterReset);
Try this solution
Goal:
add on "click" event
prevent the default action (reset)
trigger "reset"
run desired code
Example:
$("button[type='reset']").on('click', function(evt) {
evt.preventDefault();
$(evt.target).trigger('reset');
// enter code to run after reset
$.each($(this).find(":input"), function(){
$.uniform.update($(this));
});
});

Detecting mouse click on div with Javascript without side-effects

I want to detect whenever someone clicks in a div (essentially I want to know when a user is interacting with a section of text on my site, be that by selecting some text or clicking on a link), but I don't want to interfere with what the user is doing.
If I put a onmousedown or onclick event on the div it ends up breaking selection, links, etc. Is there any way to catch these events without causing any interference ?
Onmousedown or onclick shouldn't interfere with anything as long as it doesn't return false;.
You can do this:
document.getElementById("spy-on-me").onmousedown = function () {
console.log("User moused down");
return true; // Not needed, as long as you don't return false
};
If you have other scripts that are attaching behaviour via this method on the page, then to prevent overriding them you can do:
var spyElement = document.getElementById("spy-on-me");
var oldMousedown = spyElement.onmousedown;
spyElement.onmousedown = function () {
console.log("User moused down");
if(oldMousedown) oldMousedown();
};
Yes, I suspect you are currently returning false at the end of the event binding, just don't do that or any of the things in this binding:
$('a').click(function(e) {
e.stopPropagation();
e.preventDefault();
return false;
});
If you do not do any of these three things, jQuery will not stop the event from bubbling up to the browser.
Edit: Sorry didn't realise it was a plain JavaScript question.
you can use do it by adding a event listener as well
var myNode= document.querySelector('.imagegrid');
myNode.addEventListener("click",function(e){
alert(e.target+" clicked");
});
A similar example is demonstrated here
Can't you simply add a click event to the div?
<div id="secretDiv" (click)="secretDivClick()">
then on your component:
secretDivClick() {
console.log('clicked');
}

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