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How to use Javascript to execute an if/elseif/else function depending on what elements are in a div

I am creating a website where elements can be dragged and dropped from the main div with all the elements to an empty one. After you put two or more elements in the second (empty) div, you press a button which executes an if/else statement, but I want it so that the code does something if element10 and element12 are in the div, but something different if element4, element5, and element6 are in the div. Could someone help?

I would add some data to the DIVs and then use it inside of the function you just mentioned.. I think if you give enough data, you can make a dynamic call based on those data. ( or add call backs )
so for example you have this as html:
<div class="parent">
<div class="drag-able" data-name="element1" ></div>
<div class="drag-able" data-name="element2" ></div>
<div class="drag-able" data-name="element3" ></div>
<div class="drag-able" data-name="element4" ></div>
</div>
then you will have something like that in your function
//by "this" I assume you have your dragging function
switch(this.getAttribute('data-name')){
case 'element1':
// do your code
break;
case 'element2':
// do your code
break;
default : // do other code
break;
}
in fact is a little dirty but if you could provide more info and some code I could help you better. but I hope it gives you some idea about what I tried to explain.

You could track the elements using ids.
Something like this for your JavaScript, assuming that you aren't using jquery:
var if_else = function(){
var box = document.getElementById("dropIn");
var elements = box.getElementsByTagName('div');
var elm1 = elements[0];
var elm2 = elements[1];
if(elm1.id === "suchAndSuch" && elm2.id === "soAndSo"){
// do something
}
else{
//do something else
}
}
And for your HTML:
<div id="box"></div>
<div id="suchAndSuch"></div>
<div id="soAndSo"></div>
<div id="somethingElse"></div>

Why is my javascript file not re-setting a div's attribute?

I have a script that is adding and removing a class to a couple divs when a link is clicked on. Each div has a set class that does not need to be removed. However, said class is being removed. How do I stop this from happening?
HTML
<div id="home" class="page pageShowing"></div>
<div id="portfolio" class="page"></div>
JS
let holder = document.getElementById("main");
let pageShowingClass = holder.getElementsByClassName("pageShowing");
let pages = holder.getElementsByClassName("page");
Navigation.Links.forEach(function(value){
let createNavLink = document.createElement("li");
let createNavText = document.createTextNode(value.title);
createNavLink.appendChild(createNavText);
createNavList.appendChild(createNavLink);
createNavLink.addEventListener("click", function(){
let link = createNavLink.innerHTML;
link = link.toLowerCase().replace(" ", "_");
let page = document.getElementById(link);
page.setAttribute("class", "page");
for(let i = 0; i < pageShowingClass.length; i++){
Here, the click handler should only be removing the pageShowing class
if it exists but is also removing the page class
if(pageShowingClass[i].getAttribute("class") == "pageShowing"){
pageShowingClass[i].removeAttribute("class");
}
}
Here, the click handler should be readding the page class when the
link is clicked on.
page.setAttribute("class", "page");
page.setAttribute("class", "pageShowing");
page.style.display = "block";
});
});
I know it's easier to do this in jQuery, but I don't want it to be in jQuery. I also already have it to where it will add and remove the pageShowing class dynamically, so that's not an issue.

As Siguza said in the reply, you're removing the class attribute, which is what you DON'T want to be doing in this case.
Let's put the element in question here for reference:
<div id="home" class="page pageShowing"></div>
class is an attribute of the element div. When you call removeAttribute('class'), it will do as it says:
<div id="home"></div>
If you check the element in chrome's dev tools or whatever you use, you'll be seeing the element as it says above.
You're probably looking for Element.className to modify your classes, so instead of
if(pageShowingClass[i].getAttribute("class") == "pageShowing"){
pageShowingClass[i].removeAttribute("class");
}
you'll want
if(pageShowingClass[i].getAttribute("class") == "pageShowing"){
pageShowingClass[i].className = "page";
}
and if you want to add the pageShowing class again, you'd just say pageShowingClass[i].className = "page pageShowing"

Element.setAttribute() adds a new attribute or changes the value of an existing attribute on the specified element.
Use Element.classList.add(String [, String]), adds specified class values. If these classes already exist in attribute of the element, then they are ignored.
page.classList.add('page', 'pageShowing')

Javascript Collapsible Menu (hide the other elements)

I have the following working Javascript function:
function collapsible(zap) {
if (document.getElementById) {
var abra = document.getElementById(zap).style;
if (abra.display == "block") {
abra.display = "none";
} else {
abra.display = "block";
}
return false;
} else {
return true;
}
}
When I use the following in html code it displays or hides the "element" div:
<li>Element</li>
Thats working fine. But the problem is, that I want to use the function for multiple links, and then the other elements, that were clicked before, stay, open.
How can I reprogram the code, so that only one div stays open and the other gets closed if i click on another link?
Thanks beforehand!

If you could use jQuery and more importantly jQueryUI accordion I think it would accomplish exactly what you're looking for.
However, without using those two, here is how I would structure it. Like mentioned above, I would use classes to modify the styles of the divs you want shown or hidden. Then the js code can just toggle those classes on each of your elements. The slightly more difficult part (without jquery) is modifying class values since in your final application you may have lots of classes on each div. This is just a very crude example to get you going.
Working JSFiddle Example
Sample DOM
<div >
<li>Element1</li>
<div id='elem1' class='myelem visible'>
Element 1 contents
</div>
</div>
<div >
<li>Element2</li>
<div id='elem2' class='myelem'>
Element 2 contents
</div>
</div>
<div >
<li>Element3</li>
<div id='elem3' class='myelem'>
Element 3 contents
</div>
</div>
Sample JS
window['collapsible'] = function(zap) {
if (document.getElementById)
{
var visDivs = document.getElementsByClassName('visible');
for(var i = 0; i < visDivs.length; i++)
{
visDivs[i].className = visDivs[i].className.replace('visible','');
}
document.getElementById(zap).className += " visible";
return false;
}
else
return true;
}
Sample CSS:
.myelem {
display: none;
}
.visible {
display: block;
}

The way to go is to create a class(or maybe two), like collapsible and active or open that has this style(display: block or none) and then you working adding or removing the class.
The logic would be:
Links that has the class collapsible when clicked would add the active or open class which would give the behavior that remains opens(or active) by css.
If you want to hide others elements you would look for the elements with the class collapsible and then remove the active(or open) class if has any.

Here is my solution: http://jsfiddle.net/g5oc0uoq/
$('.content').hide();
$('.listelement').on('click', function(){
if(!($(this).children('.content').is(':visible'))){
$('.content').slideUp();
$(this).children('.content').slideDown();
} else {
$('.content').slideUp();
}
});
show() and hide() can be used instead of slideUp() and slideDown() if you have performance issues.

Javascript Loop Show hide elements in document (Jquery OK too)

I have a redundant process for making div's visible / hidden and I believe the way to make it more efficient is to use a loop.
Currently I have numerous div's through the document but there are 6 in particular that I want to deal with. I have a series of buttons that correspond to the six div's. When person clicks button A I want to show (make visible) div A and hide Div's B,C,D,E,F. My javascript is something like this:
<a href="#" onclick="ShowMe('A'); return false" />
<a href="#" onclick="ShowMe('B'); return false" />
<a href......etc />
<div id="A">blah...blah</div>
<div id="B">blah...blah</div>
<script type="java....">
function ShowHideDiv(DivName)
{
if(DivName == 'A')
{
var diva = document.getElementById('A');
div.style.visibility = 'visible';
var divb = document.getElementById('B');
div.style.visibility = 'hidden';
etc....
}
else if (DivName == 'B')
{
var diva = document.getElementById('A');
div.style.visibility = 'hidden';
var divb = document.getElementById('B');
div.style.visibility = 'visible';
etc...............
}
}
</script>
So as mentioned a prime candidate for loop but my question is how to contain the loop. For example if my loop went through the entire document object then I would have divs that I want visible being hidden so how do I avoid this?
I had two thought but was if others had additional thoughts, ideas, techniques etc.
Give my divs a really oddball prefix to their name like ShowHide_A then my loop can go through all the divs in the document object, parse it's name, if it doesn't have the prefix then move to the next one. This of course would be very inefficient if we had a large document and the script was getting every object and parsing then checking the name.
Wrap the div's in question in a parent container such as:
Then my javascript could be contained to looping through just the DivParent tree. But what if my div's are at different places in the document model? Do I keep them in the ParentDiv and position then where they belong with with css position properties?
Any other ideas would be greatly appreciated
JB

Let me suggest a better approach.
If you can use jQuery, you can do the following:
Assign a class (e.g. box) to all of your divs. Then your button needs to call this function:
function toggleDiv (divID) {
$(".box").hide();
$("#"+divID).show();
}
What you can also do is assign e.g. data-div attribute to your button which contains the ID of the div to hide/show, and then you can transform the above to the following (assuming your buttons have the button class):
$(".button").click(function () {
var divID = $(this).attr("data-div");
$(".box").hide();
$("#"+divID).show();
});
The above covers everything, assigning events to the buttons and hiding/showing divs.

see suppose you have markup like this
<div id="A" class="marked" >A</div>
<div id="B" class="marked" >B</div>
<div id="C" class="marked" >C</div>
<div id="D" class="marked" >D</div>
<div id="E" class="marked" >E</div>
<input type="button" value="Show A" data-target-div="A" />
<input type="button" value="Show B" data-target-div="B" />
then add a script like this:
$('input[type=button]').click(function(){
$('.marked').hide(200);
$('#'+$(this).data('target-div')).show();
});
it should work.
see this fiddle
so, you are not iterating through all the dom elements, you are picking exactly the ones you need to deal with. upon click, you hide all of them, and show the one which is target i.e. data-target-div

jQuery based solution:
Add a class to your div's that allow hiding/showing and then do
function ShowHideDiv(DivName)
{
$(".ShowHide").not("#" + DivName).hide();
$("#" + DivName).show();
}

Add class='switchable' (or whatever) to each such DIV then using prototype.js you could do something like this
function showMe( elem ) {
$$( '.switchable' ).each( function( switchable ) {
if ( switchable.id == $(elem).id )
switchable.show();
else
switchable.hide();
} );
}

How to Reduce Size of This jQuery Script and Make it More Flexible?

I just created script that shows/hides (toggles) block of HTML. There are four buttons that each can toggle its HTML block. When any HTML block is opened, but user has been clicked on other button than that HTML block's associated button... it hides that HTML block and shows new one.
Here is what I have at the moment:
$('.btn_add_event').click( function() {
$('.block_link, .block_photos, .block_videos').hide();
$('.block_event').toggle();
});
$('.btn_add_link').click( function() {
$('.block_event, .block_photos, .block_videos').hide();
$('.block_link').toggle();
});
$('.btn_add_photos').click( function() {
$('.block_event, .block_link, .block_videos').hide();
$('.block_photos').toggle();
});
$('.btn_add_videos').click( function() {
$('.block_event, .block_link, .block_photos').hide();
$('.block_videos').toggle();
});
Any ideas how to reduce code size? Also, this script isn't very flexible. Imagine to add two new buttons and blocks.

like Sam said, I would use a class that all the blocks share, so you never have to alter that code. Secondly, you can try 'traversing' to the closest block, therefore avoiding it's name. That approach is better than hard coding each specific block, but if the html dom tree changes you will need to refactor. Last, but best, you can pass in the class name desired block as a variable to the function. Below is something you can copy paste that is close to what you started with.
$('.myAddButtonClass').click( function() {
$('.mySharedBlockClass').filter(':visible').hide();
//find a good way to 'traverse' to your desired block, or name it specifically for now.
//$(this).closest(".mySharedBlockClass").show() complete guess
$('.specificBlockClass').show();
});

I kept reading this "When any HTML block is opened, but user has been clicked on other button than that HTML block's associated button" thinking that my eyes were failing me when Its just bad English.
If you want to make it more dynamic, what you can do is add a common class keyword. Then
when the click event is raise. You can have it loop though all the classes that have the
keyword and have it hide them all (except the current one that was clicked) and then show the current one by using the 'this' keyword.

you can refer below link,
http://chandreshmaheshwari.wordpress.com/2011/05/24/show-hide-div-content-using-jquery/
call function showSlidingDiv() onclick event and pass your button class dynamically.
This may be useful.
Thanks.

try this
$('input[type=button]').click( function() {
$('div[class^=block]').hide(); // I resumed html block is div
$(this).toggle();
});

Unfortunatly I couldn't test it, but if I can remember right following should work:
function toogleFunc(clickObject, toogleTarget, hideTarget)
{
$(clickObject).click(function()
{
$(hideTarget).hide();
$(toogleTarget).toggle();
});
}
And the call:
toogleFunc(
".btn_add_videos",
".block_videos",
".block_event, .block_link, .block_photos"
);
and so far

Assuming the buttons will only have one class each, something like this ought to work.
var classNames = [ 'btn_add_event', 'block_link', 'block_photos', 'block_videos' ];
var all = '.' + classNames.join(', .'); // generate a jquery format string for selection
$(all).click( function() {
var j = classNames.length;
while(j--){
if( this.className === classNames[j] ){
var others = classNames.splice(j, 1); // should leave all classes but the one on this button
$('.' + others.join(', .')).hide();
$('.' + classNames[j]).toggle();
}
}
}
All the buttons have the same handler. When the handler fires, it checks the sender for one of the classes in the list. If a class is found, it generates a jquery selection string from the remaining classes and hides them, and toggles the one found. You may have to do some checking to make sure the strings are generating correctly.

It depends by how your HTML is structured.
Supposing you've something like this
<div class="area">
<div class="one"></div>
<div class="two"></div>
<div class="three"></div>
</div>
...
<div class="sender">
<a class="one"></a>
<a class="two"></a>
<a class="three"></a>
</div>
You have a class shared by the sender and the target.
Your js would be like this:
$('.sender > a').click(function() {
var target = $(this).attr('class');
$('.area > .' + target).show().siblings().hide();
});
You show your real target and hide its siblings, which aren't needed.

If you put the class postfixes in an array, you can easily make this code more dynamic. This code assumed that it doesn't matter in which order toggle or hide are called. If it does matter, you can just remember the right classname inside the (inner) loop, and toggle that class after the loop.
The advantage to this approach is that you can extend the array with an exta class without needing to modifying the rest of the code.
var classes = new Array('videos', 'event', 'link', 'photos');
for (var i = 0; i < classes.length; ++i)
{
$('.btn_add_' + classes[i]).click(
function()
{
for (var j = 0; j < classes.length; ++j)
{
if (this.hasClass('btn_add_' + classes[j]))
{
$('.block_' + classes[j]).toggle();
}
else
{
$('.block_' + classes[j]).hide();
}
}
});
}
You could make this code more elegant by not assigning those elements classes like btn_add_event, but give them two classes: btn_add and event, or even resort to giving them id's. My solution is based on your description of your current html.

Here is what I think is a nice flexible and performant function. It assumes you can contain your links and html blocks in a parent, but otherwise it uses closures to precalculate the elements involved, so a click is super-fast.
<html>
<head>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.6.2/jquery.min.js" ></script>
<script type="text/javascript">
// Enables show/hide functionality on click.
// The elements within 'container' matching the selector 'blocks' are hidden
// When elements within 'container' matching the selector 'clicker' are clicked
// their attribute with the name 'clickerAttr' is appended to the selector
// 'subject' to identify a target, usually one of the 'blocks'. All blocks
// except the target are hidden. The target is shown.
//
// Change clickerAttr from 'linkTarget' to 'id' if you want XHTML compliance
//
// container: grouping of related elements for which to enable this functionality
// clicker: selector to element type that when clicked triggers the show/hide functionality
// clickerAttr: name of the DOM attribute that will be used to adapt the 'subject' selector
// blocks: selector to the html blocks that will be shown or hidden when the clicker is clicked
// subject: root of the selector to be used to identify the one html block to be shown
//
function initToggle(container,clicker,clickerAttr,blocks,subject) {
$(container).each(
function(idx,instance) {
var containerElement = $(instance);
var containedBlocks = containerElement.find(blocks);
containerElement.find(clicker).each(function(idxC, instanceClicker) {
var tgtE = containerElement.find(subject+instanceClicker.getAttribute(clickerAttr));
var clickerBlocks = containedBlocks.not(tgtE);
$(instanceClicker).click(function(event) {
clickerBlocks.hide();
tgtE.toggle();
});
});
// initially cleared
containedBlocks.hide();
}
);
}
$(function() {
initToggle('.toggle','a.link','linkTarget','div.block','div.');
});
</script>
</head>
<body>
Example HTML block toggle:
<div class="toggle">
a <br />
b <br />
c <br />
<div class="A block"> A </div>
<div class="B block"> B </div>
<div class="C block"> C </div>
</div> <!-- toggle -->
This next one is not enabled, to show scoping.
<div class="toggle2">
a <br />
<div class="A block">A</div>
</div> <!-- toggle2 -->
This next one is enabled, to show use in multiple positions on a page, such as in a portlet library.
<div class="toggle">
a <br />
<div class="A block">A</div>
</div> <!-- toggle (2) -->
</body>
</html>