Enable and Disable a Span class based on an even in jQuery - javascript

I have a span class which should be hidden initially and visible after an event.
<span class="badge badge-xs badge-danger">2</span>
I need it to happen on the following code:
<script>
$(document).on("DOMSubtreeModified", "#history", function () {
//add code to make span class visible
});
</script>
Wht i need is to make the class hidden on page load and make it visible after a change in #history id in a paragraph..
How is it possible through jQuery ??

You can use .show() and .hide() to change an element visibility.
$("span.badge").hide(); // or make it hidden in css by default
$(document).on("DOMSubtreeModified", "#history", function () {
$("span.badge").show();
});
The property disabled are used on input type fields only, for example in a text field you wouldn't be able to type in it. But in a span it has no effect since you can't input anything by default.

For custom Events, you have two Options:
Work with Observer. You have one subscriber and a notifier.
function Observer(){
var subscriber = [];
return{
addSubscriber: function(func){
subscriber.push(func);
},
notify: function(){
for(var i = 0; i < subscriber.length; i++){
subscriber[i]();
}
}
}
}
var observer = new Observer();
function calledOnEvent(){
$(element).hide();
}
observer.addSubscriber(calledOnEvent);
function createTheEvent(){
//Logic
observer.notify();
}
You can use eventListener and the customEvent Object.
document.addEventListener('event', aFunction);
function createAEvent(){
var event = new Event('event');
document.dispatchEvent(event);
}
In pure Javascript is the support for customEvent not really good. jQuery has a wrapper for this .trigger(): http://api.jquery.com/trigger/

Related

How can I observe changes to my DOM and react to them with jQuery?

I have this function where I toggle a class on click, but also append HTML to an element, still based on that click.
The problem is that now, I'm not listening to any DOM changes at all, so, once I do my first click, yup, my content will be added, but if I click once again - the content gets added again, because as far as this instance of jQuery is aware, the element is not there.
Here's my code:
(function($) {
"use strict";
var closePluginsList = $('#go-back-to-setup-all');
var wrapper = $('.dynamic-container');
$('#install-selected-plugins, #go-back-to-setup-all').on('click', function(event) {
$('.setup-theme-container').toggleClass('plugins-list-enabled');
if ( !wrapper.has('.plugins-container') ){
var markup = generate_plugins_list_markup();
wrapper.append(markup);
} else {
$('.plugins-container').hide();
}
});
//Below here, there's a lot of code that gets put into the markup variable. It's just generating the HTML I'm adding.
})(jQuery);
Someone suggested using data attributes, but I've no idea how to make them work in this situation.
Any ideas?
You could just do something like adding a flag and check for it before adding your markup.
var flag = 0;
$('#install-selected-plugins, #go-back-to-setup-all').on('click', function(event) {
$('.setup-theme-container').toggleClass('plugins-list-enabled');
if ( !wrapper.has('.plugins-container') ){
var markup = generate_plugins_list_markup();
if(flag == 0){
wrapper.append(markup);
flag = 1;
}
} else {
$('.plugins-container').hide();
}
});
If you want to add element once only on click then you should make use of .one() and put logic you want to execute once only in that handler.
Example :
$(document).ready(function(){
$("p").one("click", function(){
//this will get execute once only
$(this).animate({fontSize: "+=6px"});
});
$("p").on("click", function(){
//this get execute multiple times
alert('test');
});
});
html
<p>Click any p element to increase its text size. The event will only trigger once for each p element.</p>

jQuery fire function when element specific class change

I need to trigger an event when i add a specific class on button, but I have no idea how to make it listen to the class adding event.
I have something like this:
<script type="text/javascript">
$(document).ready(function() {
$(id_element).addClass("active");
//this function will fire on add "active" class to "id_button" element
function fireOnActiveClass() {
//do something
}
}
</script>
I can't touch code $(id_element).addClass("active");, for more reasons.
Currently I use jQuery 1.7.2
Could you please tell me how or which I need to know?
You are modifying the class of the control in your code. So why not simply call the click of the button when you change the class ?
$(id_element).addClass("active");
$(id_button).click();
$(id_button).click(function () {
if ($(this).hasClass) {
//do something
}
});
There is no event raised when a class changes. The alternative is to manually raise an event when you programatically change the class:
$(document).ready(function() {
$(id_element).addClass("active").trigger('classChange');
$(id_element).on('classChange', function() {
// do stuff
});
});
One other way would be to call a function right after adding the class like:
$.fn.classAdded = function() {
var $button = $(this);
if($button.hasClass('id_button')) {
// ...
}
return $button;
}
$(id_element).addClass("active").classAdded();
I have found solution using this jQuery Plugin: http://meetselva.github.io/attrchange/
Could this jQuery plugin be any help?
https://github.com/tormjens/jquery-dom-router
You can change the default element using
$.DOMRouter.defaults.element = '#element';
before initalizing the plugin.

Defining a single jQuery function for separate DOM elements

I have several jQuery click functions- each is attached to a different DOM element, and does slightly different things...
One, for example, opens and closes a dictionary, and changes the text...
$(".dictionaryFlip").click(function(){
var link = $(this);
$(".dictionaryHolder").slideToggle('fast', function() {
if ($(this).is(":visible")) {
link.text("dictionary ON");
}
else {
link.text("dictionary OFF");
}
});
});
HTML
<div class="dictionaryHolder">
<div id="dictionaryHeading">
<span class="dictionaryTitle">中 文 词 典</span>
<span class="dictionaryHeadings">Dialog</span>
<span class="dictionaryHeadings">Word Bank</span>
</div>
</div>
<p class="dictionaryFlip">toggle dictionary: off</p>
I have a separate click function for each thing I'd like to do...
Is there a way to define one click function and assign it to different DOM elements? Then maybe use if else logic to change up what's done inside the function?
Thanks!
Clarification:
I have a click function to 1) Turn on and off the dictionary, 2) Turn on and off the menu, 3) Turn on and off the minimap... etc... Just wanted to cut down on code by combining all of these into a single click function
You can of course define a single function and use it on multiple HTML elements. It's a common pattern and should be utilized if at all possible!
var onclick = function(event) {
var $elem = $(this);
alert("Clicked!");
};
$("a").click(onclick);
$(".b").click(onclick);
$("#c").click(onclick);
// jQuery can select multiple elements in one selector
$("a, .b, #c").click(onclick);
You can also store contextual information on the element using the data- custom attribute. jQuery has a nice .data function (it's simply a prefixed proxy for .attr) that allows you to easily set and retrieve keys and values on an element. Say we have a list of people, for example:
<section>
<div class="user" data-id="124124">
<h1>John Smith</h1>
<h3>Cupertino, San Franciso</h3>
</div>
</section>
Now we register a click handler on the .user class and get the id on the user:
var onclick = function(event) {
var $this = $(this), //Always good to cache your jQuery elements (if you use them more than once)
id = $this.data("id");
alert("User ID: " + id);
};
$(".user").click(onclick);
Here's a simple pattern
function a(elem){
var link = $(elem);
$(".dictionaryHolder").slideToggle('fast', function() {
if (link.is(":visible")) {
link.text("dictionary ON");
}
else {
link.text("dictionary OFF");
}
});
}
$(".dictionaryFlip").click(function(){a(this);});
$(".anotherElement").click(function(){a(this);});
Well, you could do something like:
var f = function() {
var $this = $(this);
if($this.hasClass('A')) { /* do something */ }
if($this.hasClass('B')) { /* do something else */ }
}
$('.selector').click(f);
and so inside the f function you check what was class of clicked element
and depending on that do what u wish
For better performance, you can assign only one event listener to your page. Then, use event.target to know which part was clicked and what to do.
I would put each action in a separate function, to keep code readable.
I would also recommend using a unique Id per clickable item you need.
$("body").click(function(event) {
switch(event.target.id) {
// call suitable action according to the id of clicked element
case 'dictionaryFlip':
flipDictionnary()
break;
case 'menuToggle':
toggleMenu()
break;
// other actions go here
}
});
function flipDictionnary() {
// code here
}
function toggleMenu() {
// code here
}
cf. Event Delegation with jQuery http://www.sitepoint.com/event-delegation-with-jquery/

Prototype event handler

I've defined the following HTML elements
<span class="toggle-arrow">▼</span>
<span class="toggle-arrow" style="display:none;">▶</span>
When I click on one of the elements the visibility of both should be toggled. I tried the following Prototype code:
$$('.toggle-arrow').each(function(element) {
element.observe('click', function() {
$(element).toggle();
});
});
but it doesn't work. I know everything would be much simpler if I used jQuery, but unfortunately this is not an option:
Instead of iterating through all arrows in the collection, you can use the invoke method, to bind the event handlers, as well as toggling them. Here's an example:
var arrows = $$('.toggle-arrow');
arrows.invoke("observe", "click", function () {
arrows.invoke("toggle");
});
DEMO: http://jsfiddle.net/ddMn4/
I realize this is not quite what you're asking for, but consider something like this:
<div class="toggle-arrow-container">
<span class="toggle-arrow" style="color: pink;">▶</span>
<span class="toggle-arrow" style="display:none; color: orange;">▶</span>
</div>
document.on('click', '.toggle-arrow-container .toggle-arrow', function(event, el) {
var buddies = el.up('.toggle-arrow-container').select('.toggle-arrow');
buddies.invoke('toggle');
});
This will allow you to have multiple "toggle sets" on the page. Check out the fiddle: http://jsfiddle.net/nDppd/
Hope this helps on your Prototype adventure.
Off the cuff:
function toggleArrows(e) {
e.stop();
// first discover clicked arow
var clickedArrow = e.findElement();
// second hide all arrows
$$('.toggle-arrow').invoke('hide');
// third find arrow that wasn't clicked
var arw = $$('.toggle-arrow').find(function(a) {
return a.identify() != clickedArrow.identify();
});
// fourth complete the toggle
if(arw)
arw.show();
}
Wire the toggle arrow function in document loaded event like this
document.on('click','.toggle-arrow', toggleArrows.bindAsEventListener());
That's it, however you would have more success if you took advantage of two css classes of: arrow and arrow-selected. Then you could easily write your selector using these class names to invoke your hide/show "toggle" with something like:
function toggleArrows(e) {
e.stop();
$$('.toggle-arrow').invoke('hide');
var arw = $$('.toggle-arrow').reject(function(r) {
r.hasClassName('arrow-selected'); });
$$('.arrow-selected').invoke('removeClassName', 'arrow-selected');
arw.show();
arw.addClassName('arrow-selected');
}

No events for dynamically generated input tags

I have dynamically generated some input tags for a web application.
function FormElement () {
this.formElement = $('<div class="formElement"></div>');
this.formElement.append('<label for=""></label>');
this.formElement.append('<input type="text" />');
FormElement.prototype.addIds = function (id) {
this.formElement.find('label').attr({'for':id});
this.formElement.find('input').attr({'id':id});
return this.formElement;
};
FormElement.prototype.addLabelText = function (value) {
this.formElement.find('label').html(value);
};
FormElement.prototype.addInputValue = function (value) {
this.formElement.find('input').attr({'value':value});
};
FormElement.prototype.addClass = function (className) {
this.formElement.attr({'class':className});
};
FormElement.prototype.append = function (selector) {
$(selector).append(this.formElement);
};
}
The appended elements do not seem to have associated click, select etc.. events. I read you can you .on(). I would like to associate all possible events to all types of elements in a general way. What is the best way to go about this?
Suppose you want to assign a default behavior on click event for all inputs with a specific class, say 'foo':
$(document).on('click','input.foo', function(){
/* your function here */
});
If you don't go this way and try the following:
$('input.foo').click(function(){
/* your function here */
});
then the behavior will be added only to existing elements, not to those added after the script executed.
you have to use On() function on them
Attach an event handler function for one or more events to the selected elements.
$("button").on("click", 'selector',notify);
$("target").on("change",'selector', notify);
For dynamically generated element's you need event delegation -
$(document).on('change','.yourInputClass',function(){
var value = $(this).val();
});
http://api.jquery.com/on/

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