jQuery event to trigger action when a div is made visible

Question

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.

Answer 1

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.}

Answer 2

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>

Answer 3

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');
});

Answer 4

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!

Answer 5

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...

Answer 6

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);

Answer 7

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")

Answer 8

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;
        }
    });
});

Answer 9

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");
});

Answer 10

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).

Answer 11

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
  });
});

Answer 12

Use jQuery Waypoints :

$('#contentDiv').waypoint(function() {
   alert('do something');
});

Other examples on the site of jQuery Waypoints.

Answer 13

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);

Answer 14

You can also try jQuery appear plugin as mentioned in parallel thread https://stackoverflow.com/a/3535028/741782

Answer 15

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/

Answer 16

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
});

Answer 17

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');
});

Answer 18

$(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>

Answer 19

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

Answer 20

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); }

Answer 21

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
}

Answer 22

$( 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");
    });
});

Answer 23

<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