Develop Reference

EventListener's e.preventDefault(); not working for inner-page href="#hash" links

I am currently building a WordPress site and trying to prevent inner page links for firing. The part of code I use is:
var numberLinks = Array.from( document.querySelectorAll('.benefits-links .inner-nav-link > .number-link '));
numberLinks.forEach( function (link) {
link.addEventListener('click' , numberClick)
})
function numberClick(e) {
e.preventDefault();
console.log(e);
}
When a <a></a> tag is clicked the event is logged but the window still jumps to the href anchor.
Am I missing something? How to stop the execution of the link and add my own functions?
Page of reference is https://dev.cognitivplus.com/grey-box/
Thank you

Just to make a contribution, what made the trick was to add:
e.preventDefault();
e.stopPropagation();
apparently, some relative element was triggering the link

Try bellow codes, it will work :
numberLinks.forEach( function (link) {
link.addEventListener('mouseenter',function(e){
var myLink = e.currentTarget;
myLink.khref = myLink.href;
myLink.href = "#";
});
link.addEventListener('mouseout',function(e){
var myLink = e.currentTarget;
myLink.href = myLink.khref
});
});

Hi I do it this way,
I use a specific class for all the elements i dont want to trigger.
var numberLinks = document.querySelectorAll('.benefits-links');
console.log(numberLinks);
numberLinks.forEach( function (link) {
link.addEventListener('click' , (e)=>{
e.preventDefault();
console.log("anything will trigger except pokemon");
return false
})
})
.benefits-links{
color:red;
}
Google
<br>
Pokemon
<br>
Stack Overflow
Hope it helps

window is not loading immediately after clicking a link

When I click an anchor link, the current page should be loaded again immediately:
<a href="javascript:void(0);" class="BackToFirst"
onclick="popNav('BackToFirst');">Back</a>
function popNav(type) {
if(type == "BackToFirst") {
$(".first").show();
$(".second").hide();
$('.BackToFirst').click(function() {
document.location.href = window.location.href;
});
}
}
I expect that when a user clicks on the link, the current page will load immediately but it is taking some time to load.

It is unclear what you are trying to do.
show/hide is immediately undone when you reload the page
it is recommended to use location.reload(1) instead of setting the supposedly read-only document.location
you might want to use e.preventDefault instead of the javascript void
Are you absolutely sure this is not an X/Y problem? Can you explain the actual usecase?
var current = sessionStorage.getItem("which"); // does not run in a snippet
current = current ? current.split("|") : []
if (current.length) {
$("." + current[0]).show();
$("." + current[1]).hide();
}
$(".BackToFirst").on("click", function(e) {
e.preventDefault();
$(".first").show();
$(".second").hide();
sessionStorage.setItem("which", "first|second")
setTimeout(function() {
location.reload(1); // are you absolutely sure this is not an X/Y problem?
}, 500); //let the show/hide sink in
});
Back

Your Click handler is only assigning a new click handler to the link, try this which just directly navigates:
function popNav(type){
if(type=="BackToFirst")
{
$(".first").show();
$(".second").hide();
document.location.href = window.location.href;
}
}
I think that you got two concepts mixed up, the above code attaches a DOM event to the link directly on it, the other way would be to use JQuery to attach an event to that button like so:
HTML:
Back
Script:
$('.BackToFirst').click(function(){
$(".first").show();
$(".second").hide();
document.location.href = window.location.href;
});
If you still want to check the type then data attributes are a nice way to go when working with JQuery:
Back
$('.BackToFirst').click(function(){
if($(this).data('linktype') == 'BackToFirst'){
$(".first").show();
$(".second").hide();
document.location.href = window.location.href;
}
});

I think you are overcomplicating your code. You are binding onClick after you click on the element. I think something like this should be better.
HTML:
Back
JS:
function onClickHandler(type){
if(type !== 'BackToFirst') {
return;
}
$(".first").show();
$(".second").hide();
location.reload();
}

html div onclick event

I have one html div on my jsp page, on that i have put one anchor tag, please find code below for that,
<div class="expandable-panel-heading">
<h2>
<a id="ancherComplaint" href="#addComplaint"
onclick="markActiveLink(this);">ABC</a>
</h2>
</div>
js code
$('.expandable-panel-heading:not(#ancherComplaint)').click(function () {
alert('123');
});
function markActiveLink(el) {
alert($(el).attr("id"));
}
here I when I click on div I got alert with 123 message, its fine but when I click on ABC I want message I want to call markActiveLink method.
JSFiddle
what is wrong with my code? please help me out.

The problem was that clicking the anchor still triggered a click in your <div>. That's called "event bubbling".
In fact, there are multiple solutions:
Checking in the DIV click event handler whether the actual target element was the anchor
→ jsFiddle
$('.expandable-panel-heading').click(function (evt) {
if (evt.target.tagName != "A") {
alert('123');
}
// Also possible if conditions:
// - evt.target.id != "ancherComplaint"
// - !$(evt.target).is("#ancherComplaint")
});
$("#ancherComplaint").click(function () {
alert($(this).attr("id"));
});
Stopping the event propagation from the anchor click listener
→ jsFiddle
$("#ancherComplaint").click(function (evt) {
evt.stopPropagation();
alert($(this).attr("id"));
});
As you may have noticed, I have removed the following selector part from my examples:
:not(#ancherComplaint)
This was unnecessary because there is no element with the class .expandable-panel-heading which also have #ancherComplaint as its ID.
I assume that you wanted to suppress the event for the anchor. That cannot work in that manner because both selectors (yours and mine) select the exact same DIV. The selector has no influence on the listener when it is called; it only sets the list of elements to which the listeners should be registered. Since this list is the same in both versions, there exists no difference.

Try this
$('.expandable-panel-heading:not(#ancherComplaint)').click(function () {
alert('123');
});
$('#ancherComplaint').click(function (event) {
alert($(this).attr("id"));
event.stopPropagation()
})
DEMO

Try following :
$('.expandable-panel-heading').click(function (e) {
if(e.target.nodeName == 'A'){
markActiveLink(e.target)
return;
}else{
alert('123');
}
});
function markActiveLink(el) {
alert($(el).attr("id"));
}
Here is the working demo : http://jsfiddle.net/JVrNc/4/

Change your jQuery code with this. It will alert the id of the a.
$('.expandable-panel-heading:not(#ancherComplaint)').click(function () {
markActiveLink();
alert('123');
});
function markActiveLink(el) {
var el = $('a').attr("id")
alert(el);
}
Demo

You need to read up on event bubbling and for sure remove inline event handling if you have jQuery anyway
Test the click on the div and examine the target
Live Demo
$(".expandable-panel-heading").on("click",function (e) {
if (e.target.id =="ancherComplaint") { // or test the tag
e.preventDefault(); // or e.stopPropagation()
markActiveLink(e.target);
}
else alert('123');
});
function markActiveLink(el) {
alert(el.id);
}

I would have used stopPropagation like this:
$('.expandable-panel-heading:not(#ancherComplaint)').click(function () {
alert('123');
});
$('#ancherComplaint').on('click',function(e){
e.stopPropagation();
alert('hiiiiiiiiii');
});

Try out this example, the onclick is still called from your HTML, and event bubbling is stopped.
<div class="expandable-panel-heading">
<h2>
<a id="ancherComplaint" href="#addComplaint" onclick="markActiveLink(this);event.stopPropagation();">ABC</a>
</h2>
</div>
http://jsfiddle.net/NXML7/1/

put your jquery function inside ready function for call click event:
$(document).ready(function() {
$("#ancherComplaint").click(function () {
alert($(this).attr("id"));
});
});

when click on div alert key
$(document).delegate(".searchbtn", "click", function() {
var key=$.trim($('#txtkey').val());
alert(key);
});

Prevent page scroll after click?

After clicking on the link, Click Me, the page scrolls back to the top. I do not want this. How can fix it?
Example: http://jsfiddle.net/Y6Y3Z/
Scroll-bar:
function myalert() {
var result = true;
//var hide = $('.alert').fadeOut(100);
//var css = $('#appriseOverlay').css('display','none');
var $alertDiv = $('<div class="alert">Are you sure you want to delete this item?<div class="clear"></div><button class="ok">no</button><button class="cancel">yes</button></div>');
var link = this;
$('body').append($alertDiv);
$('.ok').click(function () {
$('.alert').fadeOut(100);
$('#appriseOverlay').css('display', 'none');
callback(true, link);
});
$('.cancel').click(function () {
$('.alert').fadeOut(100);
$('#appriseOverlay').css('display', 'none');
callback(false, link);
});
$alertDiv.fadeIn(100);
$('#appriseOverlay').css('display', 'block');
return result;
};
$('.click').click(myalert);
function callback(result, link) {
//
if(result){
}
}

You only need to change the "#" to "javascript:void(0)" on HTML code:
Click Me
Another solution is add a "/" after the "#":
Click Me

The reason that it is going to the top of the page is because your anchor tag has a hash symbol as the href. The hash syntax allows you to refer to a named anchor in the document, with the link taking you to that place in the document. The default action for an anchor tag when you click on it and the href refers to a named anchor that doesn't exist is to go to the top of the page. To prevent this cancel the default action by returning false from the handler or using preventDefault on the event.
function myalert(e) {
e.preventDefault(); // <-- prevent the default action
...
return false; // <-- alternative way to prevent the default action.
};

simply prevent the default function (jump to #marker) from executing: http://jsfiddle.net/Y6Y3Z/1/

What is the opposite of evt.preventDefault();

Once I've fired an evt.preventDefault(), how can I resume default actions again?

As per commented by #Prescott, the opposite of:
evt.preventDefault();
Could be:
Essentially equating to 'do default', since we're no longer preventing it.
Otherwise I'm inclined to point you to the answers provided by another comments and answers:
How to unbind a listener that is calling event.preventDefault() (using jQuery)?
How to reenable event.preventDefault?
Note that the second one has been accepted with an example solution, given by redsquare (posted here for a direct solution in case this isn't closed as duplicate):
$('form').submit( function(ev) {
ev.preventDefault();
//later you decide you want to submit
$(this).unbind('submit').submit()
});

function(evt) {evt.preventDefault();}
and its opposite
function(evt) {return true;}
cheers!

To process a command before continue a link from a click event in jQuery:
Eg: Click me
Prevent and follow through with jQuery:
$('a.myevent').click(function(event) {
event.preventDefault();
// Do my commands
if( myEventThingFirst() )
{
// then redirect to original location
window.location = this.href;
}
else
{
alert("Couldn't do my thing first");
}
});
Or simply run window.location = this.href; after the preventDefault();

OK ! it works for the click event :
$("#submit").click(function(event){
event.preventDefault();
// -> block the click of the sumbit ... do what you want
// the html click submit work now !
$("#submit").unbind('click').click();
});

event.preventDefault(); //or event.returnValue = false;
and its opposite(standard) :
event.returnValue = true;
source:
https://developer.mozilla.org/en-US/docs/Web/API/Event/returnValue

I had to delay a form submission in jQuery in order to execute an asynchronous call. Here's the simplified code...
$("$theform").submit(function(e) {
e.preventDefault();
var $this = $(this);
$.ajax('/path/to/script.php',
{
type: "POST",
data: { value: $("#input_control").val() }
}).done(function(response) {
$this.unbind('submit').submit();
});
});

I would suggest the following pattern:
document.getElementById("foo").onsubmit = function(e) {
if (document.getElementById("test").value == "test") {
return true;
} else {
e.preventDefault();
}
}
<form id="foo">
<input id="test"/>
<input type="submit"/>
</form>
...unless I'm missing something.
http://jsfiddle.net/DdvcX/

This is what I used to set it:
$("body").on('touchmove', function(e){
e.preventDefault();
});
And to undo it:
$("body").unbind("touchmove");

There is no opposite method of event.preventDefault() to understand why you first have to look into what event.preventDefault() does when you call it.
Underneath the hood, the functionality for preventDefault is essentially calling a return false which halts any further execution. If you’re familiar with the old ways of Javascript, it was once in fashion to use return false for canceling events on things like form submits and buttons using return true (before jQuery was even around).
As you probably might have already worked out based on the simple explanation above: the opposite of event.preventDefault() is nothing. You just don’t prevent the event, by default the browser will allow the event if you are not preventing it.
See below for an explanation:
;(function($, window, document, undefined)) {
$(function() {
// By default deny the submit
var allowSubmit = false;
$("#someform").on("submit", function(event) {
if (!allowSubmit) {
event.preventDefault();
// Your code logic in here (maybe form validation or something)
// Then you set allowSubmit to true so this code is bypassed
allowSubmit = true;
}
});
});
})(jQuery, window, document);
In the code above you will notice we are checking if allowSubmit is false. This means we will prevent our form from submitting using event.preventDefault and then we will do some validation logic and if we are happy, set allowSubmit to true.
This is really the only effective method of doing the opposite of event.preventDefault() – you can also try removing events as well which essentially would achieve the same thing.

Here's something useful...
First of all we'll click on the link , run some code, and than we'll perform default action. This will be possible using event.currentTarget Take a look. Here we'll gonna try to access Google on a new tab, but before we need to run some code.
Google
<script type="text/javascript">
$(document).ready(function() {
$("#link").click(function(e) {
// Prevent default action
e.preventDefault();
// Here you'll put your code, what you want to execute before default action
alert(123);
// Prevent infinite loop
$(this).unbind('click');
// Execute default action
e.currentTarget.click();
});
});
</script>

None of the solutions helped me here and I did this to solve my situation.
<a onclick="return clickEvent(event);" href="/contact-us">
And the function clickEvent(),
function clickEvent(event) {
event.preventDefault();
// do your thing here
// remove the onclick event trigger and continue with the event
event.target.parentElement.onclick = null;
event.target.parentElement.click();
}

I supose the "opposite" would be to simulate an event. You could use .createEvent()
Following Mozilla's example:
function simulateClick() {
var evt = document.createEvent("MouseEvents");
evt.initMouseEvent("click", true, true, window,
0, 0, 0, 0, 0, false, false, false, false, 0, null);
var cb = document.getElementById("checkbox");
var cancelled = !cb.dispatchEvent(evt);
if(cancelled) {
// A handler called preventDefault
alert("cancelled");
} else {
// None of the handlers called preventDefault
alert("not cancelled");
}
}
Ref: document.createEvent
jQuery has .trigger() so you can trigger events on elements -- sometimes useful.
$('#foo').bind('click', function() {
alert($(this).text());
});
$('#foo').trigger('click');

This is not a direct answer for the question but it may help someone. My point is you only call preventDefault() based on some conditions as there is no point of having an event if you call preventDefault() for all the cases. So having if conditions and calling preventDefault() only when the condition/s satisfied will work the function in usual way for the other cases.
$('.btnEdit').click(function(e) {
var status = $(this).closest('tr').find('td').eq(3).html().trim();
var tripId = $(this).attr('tripId');
if (status == 'Completed') {
e.preventDefault();
alert("You can't edit completed reservations");
} else if (tripId != '') {
e.preventDefault();
alert("You can't edit a reservation which is already attached to a trip");
}
//else it will continue as usual
});

jquery on() could be another solution to this. escpacially when it comes to the use of namespaces.
jquery on() is just the current way of binding events ( instead of bind() ). off() is to unbind these. and when you use a namespace, you can add and remove multiple different events.
$( selector ).on("submit.my-namespace", function( event ) {
//prevent the event
event.preventDefault();
//cache the selector
var $this = $(this);
if ( my_condition_is_true ) {
//when 'my_condition_is_true' is met, the binding is removed and the event is triggered again.
$this.off("submit.my-namespace").trigger("submit");
}
});
now with the use of namespace, you could add multiple of these events and are able to remove those, depending on your needs.. while submit might not be the best example, this might come in handy on a click or keypress or whatever..

you can use this after "preventDefault" method
//Here evt.target return default event (eg : defult url etc)
var defaultEvent=evt.target;
//Here we save default event ..
if("true")
{
//activate default event..
location.href(defaultEvent);
}

You can always use this attached to some click event in your script:
location.href = this.href;
example of usage is:
jQuery('a').click(function(e) {
location.href = this.href;
});

In a Synchronous flow, you call e.preventDefault() only when you need to:
a_link.addEventListener('click', (e) => {
if( conditionFailed ) {
e.preventDefault();
// return;
}
// continue with default behaviour i.e redirect to href
});
In an Asynchronous flow, you have many ways but one that is quite common is using window.location:
a_link.addEventListener('click', (e) => {
e.preventDefault(); // prevent default any way
const self = this;
call_returning_promise()
.then(res => {
if(res) {
window.location.replace( self.href );
}
});
});
You can for sure make the above flow synchronous by using async-await

this code worked for me to re-instantiate the event after i had used :
event.preventDefault(); to disable the event.
event.preventDefault = false;

I have used the following code. It works fine for me.
$('a').bind('click', function(e) {
e.stopPropagation();
});