I'm making a basic jQuery plugin with which the user can change Bg-color, font-color etc.
I want the user of the plugin to be able to define the elements on which these changes become active.
I know I have to use 'this' but I don't know how to do it.
This is the code for the plugin
(function($, window, document, undefined){
//Define your own variables first
var wrapper = $('.wrapper');
var p = $('p');
//Define the default settings here
var settings = {
textColor: 'red'
};
//Write your methods here
var methods = {
//Call this method to initialize the plugin
init: function(){
console.log("Initialize the plugin");
$('input').on('change', methods.changeColor);
$('select').on('change', methods.changeFont);
$('.slider').on('change', methods.changeWidth);
},
changeColor: function(){
console.log("This will change the background and/or font color");
var userBackgroundColor = $("#userBackgroundColor").val();
var userTextColor = $("#userTextColor").val().toLocaleLowerCase();
wrapper.css({
backgroundColor: userBackgroundColor,
color: userTextColor
});
},
changeFont: function(){
console.log("This will change the font");
var userFontSize = $("option:selected").val();
console.log(userFontSize);
p.css({
fontSize: userFontSize + 'em'
})
},
changeWidth: function(){
var p = $('p');
var userWidth = $(".slider").val();
var widthFontChange = userWidth / 20;
if (widthFontChange == 1) {
p.css({
width: userWidth + '%',
fontSize: widthFontChange + 'em'
});
}
else {
widthFontChange = userWidth / 2;
p.css({
width: userWidth + '%',
fontSize: widthFontChange + 'px'
})
}
}
};
//Actual plugin call
$.fn.pluginName = function(options){
//If the user overrides defaults by setting his own options
if(options){
settings = $.extend(settings, options);
}
//Put any eventHandlers here, like this:
this.on('change', methods.changeColor);
this.on('change', methods.changeFont);
this.on('change', methods.changeWidth);
//Init the plugin with the $selector
methods.init(this);
//Return this for jQuery chaining
return this;
};
}(jQuery, window, document));
And this is the file in which the user wil be able to define the object on which the plugin has to work
$(document).ready(function(){
$('body').pluginName();
});
My question is, how to I make this work the way I want it to?
If I understand your question correctly, you want to provide settings to choose the various components to listen for changes. If so...
Pass the jQuery this and the options to your init method, so it has everything it needs to hook up events to specific child elements.
I switched to using the delegated version of on as it will survive dynamic changes.
JSFiddle: http://jsfiddle.net/CgGjq/6/
The key part is
init: function ($element, options) {
console.log("Initialize the plugin");
$element.on('change', options.input || 'input', methods.changeColor);
$element.on('change', options.select || 'select', methods.changeFont);
$element.on('change', options.slider || '.slider', methods.changeWidth);
},
Which uses properties in the options to override the selectors (or default to your plugin defaults settings if not supplied).
You can then use it with options like this:
$(document).ready(function () {
$('body').pluginName({
select: '#userFontSize', // Override the selectors etc
slider: "#userWidth.slider"
});
});
What I am trying to achieve is that whenever you click an image, it changes the window.location url, toggling it between '#' and '#footer'. Right now, all I have is this:
<script>
function clickarrow(){
var rd=Math.floor(Math.random()*11)
if (rd > 5){
window.location="#footer";
}
else{
window.location="#";
}
}
</script>
As you can see, this makes a 50:50 chance of either change being made. It works as a temparary fix, but sometimes you have to click up to 6 times for it to take effect.
Is there a way of doing this that properly toggles the window.location?
I am using jQuery 1.9.
If you're trying to reliably toggle the hash, rather than using a random chance, try something like this:
function clickarrow(){
var showFooter = true;
return function () {
if (showFooter) {
window.location.hash = "footer";
} else {
window.location.hash = "";
}
showFooter = !showFooter;
}
}
jQuery(function () {
jQuery('#myToggleLink').click(clickarrow());
});
Note: Normally when binding events, a function reference must be passed in. Here, I'm invoking clickarrow() since it returns a function by design. The returned function encapsulates the toggle variable via closure.
you can use data attribute to tell what is next step:
$('#arrow').click(function() {
if ($(this).data('footer'))
{
window.location="#footer";
$(this).data('footer', 'false');
alert('b');
}
else
{
window.location="#";
$(this).data('footer', 'true');
alert('a');
}
});
Quick Description:
I'm aware that using $(this) in a function won't work because it's not within the right scope. I've also seen other similar questions. I just still can't figure out how to fix my scenerio.
Goal: I'm trying to build a panoramic photo viewer with jQuery. I have it working, but I need multiple instances. So I need to target only the one I'm hovering on.
Code:
jsFiddle: http://jsfiddle.net/kthornbloom/5J3rh/
Simplified Code:
var hoverInterval;
function doStuff() {
/* The next line is the one in question */
$(this).animate({
/* stuff happening */
});
}
$(function() {
$('.pan-wrap').hover(
function() {
/* stuff happening */
hoverInterval = setInterval(doStuff, 250);
},
function() {
clearInterval(hoverInterval);
});
});
You have scope issues, this in the doStuff is window context.
Use proxy()
hoverInterval = setInterval($.proxy(doStuff,this), 250);
You can explicitly pass this into doStuff:
setInterval(function() {
doStuff(this);
}, 250);
And in doStuff you can do:
function doStuff(element) {
...
}
Or you can explicitly set the value of this for doStuff like so:
setInterval(function() {
doStuff.call(this);
}, 250);
Then you can still use $(this) inside doStuff without changing any of its arguments. For more information on call, see Function.prototype.call and its friend Function.prototype.apply.
I know that I can create custom jQuery plugins by using the $.fn.myFunction constructor, and the calling the custom function in JavaScript as $('selector').myFunction().
However, for a project I'm currently working on, I need to be able to define a function that does not require a selector to work.This is actually for a MessageBox plugin, which will act in a similar manner to C#'s MessageBox class. As such, I would ideally like to create the function as MessageBox, and then call it as follows:
var myMessage = $.MessageBox(); and then in turn myMessage.Show();
Notice the lack of selector brakets in the jQuery reference at the beginning of the function call.
Any advice on the best practice for this would be gratefully received.
This should work:
jQuery.MessageBox = function() {
var show = function() {
// something...
}
var hide = function() {
// something...
}
return {
show: show,
hide: hide
}
}
relipse has a good point - as you are cluttering the main namespace. A solution if you have more objects than just eg. MessageBox is to create your own namespace like this:
jQuery.myLib = {
MessageBox: function() {
var show = function() {
// something...
}
var hide = function() {
// something...
}
return {
show: show,
hide: hide
}
}
}
That means you are only taking one place in the main namespace (the name of your library, in this case myLib). You'd call it like this:
jQuery.myLib.MessageBox.show()
(function ($) {
$.MessageBox = function () {
var show = function () {
// something...
}
var hide = function () {
// something...
}
return {
show: show,
hide: hide
}
}
})(Jquery);
I think you better scope to Immediate invocation function to avoid collision with namespaces.
I'm using jQuery in my site and I would like to trigger certain actions when a certain div is made visible.
Is it possible to attach some sort of "isvisible" event handler to arbitrary divs and have certain code run when they the div is made visible?
I would like something like the following pseudocode:
$(function() {
$('#contentDiv').isvisible(function() {
alert("do something");
});
});
The alert("do something") code should not fire until the contentDiv is actually made visible.
Thanks.
You could always add to the original .show() method so you don't have to trigger events every time you show something or if you need it to work with legacy code:
Jquery extension:
jQuery(function($) {
var _oldShow = $.fn.show;
$.fn.show = function(speed, oldCallback) {
return $(this).each(function() {
var obj = $(this),
newCallback = function() {
if ($.isFunction(oldCallback)) {
oldCallback.apply(obj);
}
obj.trigger('afterShow');
};
// you can trigger a before show if you want
obj.trigger('beforeShow');
// now use the old function to show the element passing the new callback
_oldShow.apply(obj, [speed, newCallback]);
});
}
});
Usage example:
jQuery(function($) {
$('#test')
.bind('beforeShow', function() {
alert('beforeShow');
})
.bind('afterShow', function() {
alert('afterShow');
})
.show(1000, function() {
alert('in show callback');
})
.show();
});
This effectively lets you do something beforeShow and afterShow while still executing the normal behavior of the original .show() method.
You could also create another method so you don't have to override the original .show() method.
The problem is being addressed by DOM mutation observers. They allow you to bind an observer (a function) to events of changing content, text or attributes of dom elements.
With the release of IE11, all major browsers support this feature, check http://caniuse.com/mutationobserver
The example code is a follows:
$(function() {
$('#show').click(function() {
$('#testdiv').show();
});
var observer = new MutationObserver(function(mutations) {
alert('Attributes changed!');
});
var target = document.querySelector('#testdiv');
observer.observe(target, {
attributes: true
});
});
<div id="testdiv" style="display:none;">hidden</div>
<button id="show">Show hidden div</button>
<script type="text/javascript" src="https://code.jquery.com/jquery-1.9.1.min.js"></script>
There is no native event you can hook into for this however you can trigger an event from your script after you have made the div visible using the .trigger function
e.g
//declare event to run when div is visible
function isVisible(){
//do something
}
//hookup the event
$('#someDivId').bind('isVisible', isVisible);
//show div and trigger custom event in callback when div is visible
$('#someDivId').show('slow', function(){
$(this).trigger('isVisible');
});
You can use jQuery's Live Query plugin.
And write code as follows:
$('#contentDiv:visible').livequery(function() {
alert("do something");
});
Then everytime the contentDiv is visible, "do something" will be alerted!
redsquare's solution is the right answer.
But as an IN-THEORY solution you can write a function which is selecting the elements classed by .visibilityCheck (not all visible elements) and check their visibility property value; if true then do something.
Afterward, the function should be performed periodically using the setInterval() function. You can stop the timer using the clearInterval() upon successful call-out.
Here's an example:
function foo() {
$('.visibilityCheck').each(function() {
if ($(this).is(':visible')){
// do something
}
});
}
window.setInterval(foo, 100);
You can also perform some performance improvements on it, however, the solution is basically absurd to be used in action. So...
The following code (pulled from http://maximeparmentier.com/2012/11/06/bind-show-hide-events-with-jquery/) will enable you to use $('#someDiv').on('show', someFunc);.
(function ($) {
$.each(['show', 'hide'], function (i, ev) {
var el = $.fn[ev];
$.fn[ev] = function () {
this.trigger(ev);
return el.apply(this, arguments);
};
});
})(jQuery);
If you want to trigger the event on all elements (and child elements) that are actually made visible, by $.show, toggle, toggleClass, addClass, or removeClass:
$.each(["show", "toggle", "toggleClass", "addClass", "removeClass"], function(){
var _oldFn = $.fn[this];
$.fn[this] = function(){
var hidden = this.find(":hidden").add(this.filter(":hidden"));
var result = _oldFn.apply(this, arguments);
hidden.filter(":visible").each(function(){
$(this).triggerHandler("show"); //No bubbling
});
return result;
}
});
And now your element:
$("#myLazyUl").bind("show", function(){
alert(this);
});
You could add overrides to additional jQuery functions by adding them to the array at the top (like "attr")
a hide/show event trigger based on Glenns ideea:
removed toggle because it fires show/hide and we don't want 2fires for one event
$(function(){
$.each(["show","hide", "toggleClass", "addClass", "removeClass"], function(){
var _oldFn = $.fn[this];
$.fn[this] = function(){
var hidden = this.find(":hidden").add(this.filter(":hidden"));
var visible = this.find(":visible").add(this.filter(":visible"));
var result = _oldFn.apply(this, arguments);
hidden.filter(":visible").each(function(){
$(this).triggerHandler("show");
});
visible.filter(":hidden").each(function(){
$(this).triggerHandler("hide");
});
return result;
}
});
});
I had this same problem and created a jQuery plugin to solve it for our site.
https://github.com/shaunbowe/jquery.visibilityChanged
Here is how you would use it based on your example:
$('#contentDiv').visibilityChanged(function(element, visible) {
alert("do something");
});
What helped me here is recent ResizeObserver spec polyfill:
const divEl = $('#section60');
const ro = new ResizeObserver(() => {
if (divEl.is(':visible')) {
console.log("it's visible now!");
}
});
ro.observe(divEl[0]);
Note that it's crossbrowser and performant (no polling).
Just bind a trigger with the selector and put the code into the trigger event:
jQuery(function() {
jQuery("#contentDiv:hidden").show().trigger('show');
jQuery('#contentDiv').on('show', function() {
console.log('#contentDiv is now visible');
// your code here
});
});
Use jQuery Waypoints :
$('#contentDiv').waypoint(function() {
alert('do something');
});
Other examples on the site of jQuery Waypoints.
I did a simple setinterval function to achieve this. If element with class div1 is visible, it sets div2 to be visible. I know not a good method, but a simple fix.
setInterval(function(){
if($('.div1').is(':visible')){
$('.div2').show();
}
else {
$('.div2').hide();
}
}, 100);
You can also try jQuery appear plugin as mentioned in parallel thread https://stackoverflow.com/a/3535028/741782
This support easing and trigger event after animation done! [tested on jQuery 2.2.4]
(function ($) {
$.each(['show', 'hide', 'fadeOut', 'fadeIn'], function (i, ev) {
var el = $.fn[ev];
$.fn[ev] = function () {
var result = el.apply(this, arguments);
var _self=this;
result.promise().done(function () {
_self.triggerHandler(ev, [result]);
//console.log(_self);
});
return result;
};
});
})(jQuery);
Inspired By http://viralpatel.net/blogs/jquery-trigger-custom-event-show-hide-element/
There is a jQuery plugin available for watching change in DOM attributes,
https://github.com/darcyclarke/jQuery-Watch-Plugin
The plugin wraps All you need do is bind MutationObserver
You can then use it to watch the div using:
$("#selector").watch('css', function() {
console.log("Visibility: " + this.style.display == 'none'?'hidden':'shown'));
//or any random events
});
Hope this will do the job in simplest manner:
$("#myID").on('show').trigger('displayShow');
$('#myID').off('displayShow').on('displayShow', function(e) {
console.log('This event will be triggered when myID will be visible');
});
I changed the hide/show event trigger from Catalint based on Glenns idea.
My problem was that I have a modular application. I change between modules showing and hiding divs parents. Then when I hide a module and show another one, with his method I have a visible delay when I change between modules. I only need sometimes to liten this event, and in some special childs. So I decided to notify only the childs with the class "displayObserver"
$.each(["show", "hide", "toggleClass", "addClass", "removeClass"], function () {
var _oldFn = $.fn[this];
$.fn[this] = function () {
var hidden = this.find(".displayObserver:hidden").add(this.filter(":hidden"));
var visible = this.find(".displayObserver:visible").add(this.filter(":visible"));
var result = _oldFn.apply(this, arguments);
hidden.filter(":visible").each(function () {
$(this).triggerHandler("show");
});
visible.filter(":hidden").each(function () {
$(this).triggerHandler("hide");
});
return result;
}
});
Then when a child wants to listen for "show" or "hide" event I have to add him the class "displayObserver", and when It does not want to continue listen it, I remove him the class
bindDisplayEvent: function () {
$("#child1").addClass("displayObserver");
$("#child1").off("show", this.onParentShow);
$("#child1").on("show", this.onParentShow);
},
bindDisplayEvent: function () {
$("#child1").removeClass("displayObserver");
$("#child1").off("show", this.onParentShow);
},
I wish help
One way to do this.
Works only on visibility changes that are made by css class change, but can be extended to watch for attribute changes too.
var observer = new MutationObserver(function(mutations) {
var clone = $(mutations[0].target).clone();
clone.removeClass();
for(var i = 0; i < mutations.length; i++){
clone.addClass(mutations[i].oldValue);
}
$(document.body).append(clone);
var cloneVisibility = $(clone).is(":visible");
$(clone).remove();
if (cloneVisibility != $(mutations[0].target).is(":visible")){
var visibilityChangedEvent = document.createEvent('Event');
visibilityChangedEvent.initEvent('visibilityChanged', true, true);
mutations[0].target.dispatchEvent(visibilityChangedEvent);
}
});
var targets = $('.ui-collapsible-content');
$.each(targets, function(i,target){
target.addEventListener('visibilityChanged',VisbilityChanedEventHandler});
target.addEventListener('DOMNodeRemovedFromDocument',VisbilityChanedEventHandler });
observer.observe(target, { attributes: true, attributeFilter : ['class'], childList: false, attributeOldValue: true });
});
function VisbilityChanedEventHandler(e){console.log('Kaboom babe'); console.log(e.target); }
my solution:
; (function ($) {
$.each([ "toggle", "show", "hide" ], function( i, name ) {
var cssFn = $.fn[ name ];
$.fn[ name ] = function( speed, easing, callback ) {
if(speed == null || typeof speed === "boolean"){
var ret=cssFn.apply( this, arguments )
$.fn.triggerVisibleEvent.apply(this,arguments)
return ret
}else{
var that=this
var new_callback=function(){
callback.call(this)
$.fn.triggerVisibleEvent.apply(that,arguments)
}
var ret=this.animate( genFx( name, true ), speed, easing, new_callback )
return ret
}
};
});
$.fn.triggerVisibleEvent=function(){
this.each(function(){
if($(this).is(':visible')){
$(this).trigger('visible')
$(this).find('[data-trigger-visible-event]').triggerVisibleEvent()
}
})
}
})(jQuery);
example usage:
if(!$info_center.is(':visible')){
$info_center.attr('data-trigger-visible-event','true').one('visible',processMoreLessButton)
}else{
processMoreLessButton()
}
function processMoreLessButton(){
//some logic
}
$( window ).scroll(function(e,i) {
win_top = $( window ).scrollTop();
win_bottom = $( window ).height() + win_top;
//console.log( win_top,win_bottom );
$('.onvisible').each(function()
{
t = $(this).offset().top;
b = t + $(this).height();
if( t > win_top && b < win_bottom )
alert("do something");
});
});
$(function() {
$(document).click(function (){
if ($('#contentDiv').is(':visible')) {
alert("Visible");
} else {
alert("Hidden");
}
});
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div id="contentDiv">Test I'm here</div>
<button onclick="$('#contentDiv').toggle();">Toggle the div</button>
<div id="welcometo">Özhan</div>
<input type="button" name="ooo"
onclick="JavaScript:
if(document.all.welcometo.style.display=='none') {
document.all.welcometo.style.display='';
} else {
document.all.welcometo.style.display='none';
}">
This code auto control not required query visible or unvisible control