How to unbind a listener that is calling event.preventDefault() (using jQuery)?

jquery toggle calls preventDefault() by default, so the defaults don't work. you can't click a checkbox, you cant click a link etc etc

is it possible to restore the default hand开发者_运维知识库ler?

In my case:

$('#some_link').click(function(event){
    event.preventDefault();
});

$('#some_link').unbind('click'); worked as the only method to restore the default action.

As seen over here: https://stackoverflow.com/a/1673570/211514

Its fairly simple

Lets suppose you do something like

document.ontouchmove = function(e){ e.preventDefault(); }

now to revert it to the original situation, do the below...

document.ontouchmove = function(e){ return true; }

From this website.

It is not possible to restore a preventDefault() but what you can do is trick it :)

<div id="t1">Toggle</div>
<script type="javascript">
$('#t1').click(function (e){
   if($(this).hasClass('prevented')){
       e.preventDefault();
       $(this).removeClass('prevented');
   }else{
       $(this).addClass('prevented');
   }
});
</script>

If you want to go a step further you can even use the trigger button to trigger an event.

function DoPrevent(e) {
  e.preventDefault();
  e.stopPropagation();
}

// Bind:
$(element).on('click', DoPrevent);

// UnBind:
$(element).off('click', DoPrevent);

in some cases* you can initially return false instead of e.preventDefault(), then when you want to restore the default to return true.

*Meaning when you don't mind the event bubbling and you don't use the e.stopPropagation() together with e.preventDefault()

Also see similar question (also in stack Overflow)

or in the case of checkbox you can have something like:

$(element).toggle(function(){
  $(":checkbox").attr('disabled', true);
  },
function(){
   $(":checkbox").removeAttr('disabled');
}) 

You can restore the default action (if it is a HREF follow) by doing this:

window.location = $(this).attr('href');

if it is a link then $(this).unbind("click"); would re-enable the link clicking and the default behavior would be restored.

I have created a demo JS fiddle to demonstrate how this works:

Here is the code of the JS fiddle:

HTML:

<script src="https://code.jquery.com/jquery-1.10.2.js"></script>
<a href="http://jquery.com">Default click action is prevented, only on the third click it would be enabled</a>
<div id="log"></div>

Javascript:

<script>
var counter = 1;
$(document).ready(function(){
$( "a" ).click(function( event ) {
  event.preventDefault();

  $( "<div>" )
    .append( "default " + event.type + " prevented "+counter )
    .appendTo( "#log" );

    if(counter == 2)
    {
        $( "<div>" )
    .append( "now enable click" )
    .appendTo( "#log" );

    $(this).unbind("click");//-----this code unbinds the e.preventDefault() and restores the link clicking behavior
    }
    else
    {
        $( "<div>" )
    .append( "still disabled" )
    .appendTo( "#log" );
    }
    counter++;
});
});
</script>

Test this code, I think solve your problem:

event.stopPropagation();

Reference

The best way to do this by using namespace. It is a safe and secure way. Here .rb is the namespace which ensures unbind function works on that particular keydown but not on others.

$(document).bind('keydown.rb','Ctrl+r',function(e){
            e.stopImmediatePropagation();
            return false;
        });

$(document).unbind('keydown.rb');

ref1: http://idodev.co.uk/2014/01/safely-binding-to-events-using-namespaces-in-jquery/

ref2: http://jqfundamentals.com/chapter/events

If the element only has one handler, then simply use jQuery unbind.

$("#element").unbind();

Disable:

document.ontouchstart = function(e){ e.preventDefault(); }

Enable:

document.ontouchstart = function(e){ return true; }

The Event interface's preventDefault() method tells the user agent that if the event does not get explicitly handled, its default action should not be taken as it normally would be. The event continues to propagate as usual, unless one of its event listeners calls stopPropagation() or stopImmediatePropagation(), either of which terminates propagation at once.

Calling preventDefault() during any stage of event flow cancels the event, meaning that any default action normally taken by the implementation as a result of the event will not occur.

You can use Event.cancelable to check if the event is cancelable. Calling preventDefault() for a non-cancelable event has no effect.

window.onKeydown = event => {
    /*
        if the control button is pressed, the event.ctrKey 
        will be the value  [true]
    */

    if (event.ctrKey && event.keyCode == 83) {
        event.preventDefault();
        // you function in here.
    }
}

I had a problem where I needed the default action only after some custom action (enable otherwise disabled input fields on a form) had concluded. I wrapped the default action (submit()) into an own, recursive function (dosubmit()).

var prevdef=true;
var dosubmit=function(){
    if(prevdef==true){
        //here we can do something else first//
        prevdef=false;
        dosubmit();
    }
    else{
        $(this).submit();//which was the default action
    }
};

$('input#somebutton').click(function(){dosubmit()});

Use a boolean:

let prevent_touch = true;
document.documentElement.addEventListener('touchmove', touchMove, false);
function touchMove(event) { 
    if (prevent_touch) event.preventDefault(); 
}

I use this in a Progressive Web App to prevent scrolling/zooming on some 'pages' while allowing on others.

You can set to form 2 classes. After you set your JS script to one of them, when you want to disable your script, you just delete the class with binded script from this form.

HTML:

<form class="form-create-container form-create"> </form>   

JS

$(document).on('submit', '.form-create', function(){ 
..... ..... ..... 
$('.form-create-container').removeClass('form-create').submit();

});

in javacript you can simply like this

const form = document.getElementById('form');
form.addEventListener('submit', function(event){
  event.preventDefault();

  const fromdate = document.getElementById('fromdate').value;
  const todate = document.getElementById('todate').value;

  if(Number(fromdate) >= Number(todate)) {
    alert('Invalid Date. please check and try again!');
  }else{
    event.currentTarget.submit();
  }

});

Worked as the only method to restore the default action.

$('#some_link').unbind();

This should work:

$('#myform').on('submit',function(e){
    if($(".field").val()==''){
        e.preventDefault();
    }
}); 

$('#my_elementtt').click(function(event){
    trigger('click');
});

I'm not sure you're what you mean: but here's a solution for a similar (and possibly the same) problem...

I often use preventDefault() to intercept items. However: it's not the only method of interception... often you may just want a "question" following which behaviour continues as before, or stops. In a recent case I used the following solution:

$("#content").on('click', '#replace', (function(event){ return confirm('Are you sure you want to do that?') }));

Basically, the "prevent default" is meant to intercept and do something else: the "confirm" is designed for use in ... well - confirming!