Develop Reference

if one item is clicked, remove the other items?

I'm learning Javascript and jQuery and I'm stuck at this one problem. Let's say my code looks like this:
<div id="hey"> hey </div>
<div id="how"> how </div>
<div id="are"> are </div>
<div id="you"> you </div>
Now, if i click one of the div's, i want the other ones to disappear.
I know, I could create 4 functions for each one of them with on.click hey and display none with how , are and you. But is there a easier way? I bet there is, with classes maybe?
Thanks for responding!

Use siblings to get reference to its "brothers".
Given a jQuery object that represents a set of DOM elements, the .siblings() method allows us to search through the siblings of these elements in the DOM tree and construct a new jQuery object from the matching elements.
$('div').click(function(){
$(this).siblings().hide();
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="hey"> hey </div>
<div id="how"> how </div>
<div id="are"> are </div>
<div id="you"> you </div>
Or you can hide all the other div which not the clicked element using not
Remove elements from the set of matched elements.
$('div').click(function() {
$('div').not(this).hide();
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="hey"> hey </div>
<div id="how"> how </div>
<div id="are"> are </div>
<div id="you"> you </div>

You can just hide siblings() of clicked div.
$('div').click(function() {
$(this).siblings().fadeOut()
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="hey">hey</div>
<div id="how">how</div>
<div id="are">are</div>
<div id="you">you</div>

Yeah there are some easier ways and I could tell a one from it,
Set a common class to all the elements that you are gonna target,
<div class="clickable" id="hey"> hey </div>
<div class="clickable" id="how"> how </div>
<div class="clickable" id="are"> are </div>
<div class="clickable" id="you"> you </div>
And you have to bind a single click event by using a class selector,
$(".clickable").on("click", function(){ });
Now use the .siblings() functions to hide the required elements,
$(".clickable").on("click", function(){
$(this).siblings(".clickable").hide();
});
But using a toggle instead of hide would sounds logical,
$(".clickable").on("click", function(){
$(this).siblings(".clickable").toggle();
});
Since you can do the same operation over all the elements.

You can use not to avoid element and this will indicate current instance.
$(document).ready(function(){
$("div").on("click",function(){
$("div").not(this).hide("slow");
})
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="hey"> hey </div>
<div id="how"> how </div>
<div id="are"> are </div>
<div id="you"> you </div>

Assign a class to each of the elements:
<div id="hey" class='sth'> hey </div>
<div id="how" class='sth'> how </div>
<div id="are" class='sth'> are </div>
<div id="you"class='sth' > you </div>
And write a js function onclick.
Remove class 'sth' from 'this' element in this function
Hide all elements with class 'sth' $('.sth').hide();

For this example - you don't need to add any further selectors to target the div's although in reality - this solution wwould cause all divs on the page to be affectecd - adding classes would be my actual suggestion: - but this works for this example. Click a div and all divs are hidden then the clicked one is shown. I also added a reset button to allow all divs to reappear.
$('div').click(function(){
$('div').hide();
$(this).show();
});
$('#reset').click(function(){
$('div').show();
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="hey"> hey </div>
<div id="how"> how </div>
<div id="are"> are </div>
<div id="you"> you </div>
<hr/>
<button type="button" id="reset">Reset</button>

$(document).ready(function(){
$("div").on("click",function(){
$("div").not(this).toggle("slow");
})
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="hey"> hey </div>
<div id="how"> how </div>
<div id="are"> are </div>
<div id="you"> you </div>

How to find specific class name in html

I am new and start to learn writing html. In my code, the situation would be that when I click to a button, I used $(event.currentTarget).parents('.page-container') to get the whole html element of my currentTarget and then I have all elements like below:
<div class="page-container">
<div id="mainContainer" class="container-fluid">
<div class="row row-offcanvas row-offcanvas-left">
<div id="accordionSummaryList" class="sidebar-left col-lg-2 col-md-2 col-sm-2 sidebar-offcanvas">
<div class="mainTenant">
<div class="subTenant">
<h5 data-toggle="collapse" data-parent="#accordionSummaryList" href="#toggleAbleListGroup1">Admins</h5>
<div class="container-fluid panel-collapse collapse in" id="toggleAbleListGroup1"></div>
</div>
</div>
</div>
</div>
</div>
</div>
What I would like to do is I would like to find all of the div element which have the class = "collapse in" and I want to remove the class "in" to hide the content inside of this div box.
How can I do that?

in vanilla-JS
[].forEach.call(document.querySelectorAll('.subTenant .collapse.in'), function(el){
el.classList.remove('in');
}
or with jQuery (if already included)
$('.subTenant .collapse.in').removeClass('in');

If you want to do it with jquery: $(".collapse.in").removeClass("in")

you can do it with jquery
jQuery('.collapse').removeClass('in');

You can also do it with this
if($(event.currentTarget).parents('.page-container').find('.collapse'))
{
$('.collapse').removeClass('in');
}

jQuery select closest child element by class

How would I use jQuery to get get the text from the rating selected div within the id=overall answer div?
I want to dynamically fetch the text "TESTING" from that div within the overall parent div.
<div class='answer' id="overall">
<div class='rating'>1</div>
<div class='rating'>2</div>
<div class='rating'>3</div>
<div class='rating'>4</div>
<div class='rating selected'>TESTING</div>
</div>
<div class='answer' id="effort">
<div class='rating'>1</div>
<div class='rating'>2</div>
<div class='rating'>3</div>
<div class='rating selected'>4</div>
<div class='rating'>TESTING</div>
</div>
I tried to do this and it is blank.
$(document.getElementById('overall')).find('.rating selected').text();

Your code would work but your selector is wrong. It would be...
$(document.getElementById('overall')).find('.rating.selected').text();
Notice the dot and no space between rating and selected.
However, I think you are over complicating things...
$('#overall .selected').text();
Example...
alert($('#overall .selected').text());
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
<div class='answer' id="overall">
<div class='rating'>1</div>
<div class='rating'>2</div>
<div class='rating'>3</div>
<div class='rating'>4</div>
<div class='rating selected'>TESTING - selected</div>
</div>
<div class='answer' id="effort">
<div class='rating'>1</div>
<div class='rating'>2</div>
<div class='rating'>3</div>
<div class='rating selected'>4</div>
<div class='rating'>TESTING - not selected</div>
</div>

$('#overall .rating.selected').html()

dropzone.js programmatically doesn't work

I am trying create drop zones programmatically, but it doesn't work.
HTML Code:
<div class="content-wrap">
<div class="row">
<script type="text/javascript">
$(function() {
$("div#myDropZone").dropzone({
url : "/file-upload"
});
});
</script>
<div class="col-sm-12">
<div class="nest" id="DropZoneClose">
<div class="title-alt">
<h6>DropZone</h6>
</div>
<div class="body-nest" id="DropZone">
<div id="myDropZone" >
</div>
<button style="margin-top: 10px;" class="btn btn-info"
id="submit-all">Submit all files</button>
</div>
</div>
</div>
</div>
</div>
The drop zone in <div id="myDropZone"> not appers!
best regards :)

You need to give your #myDropZone div some width and height so that it takes up space. Heres a jsfiddle.
Alternatively, you can add the dropzone class to your div to get the default styling that you see in the demos. Heres the jsfiddle for that.

Add class dropzone to the div element which holds your drop zone.
Hope that you have added the dropzone stylesheet to your page.

Javascript click specific to ID

I have a div setup like so:
<div class="content">
<button class="show-comments" id="content1"></button>
</div>
<div class="comments-wrapper" id="comment1"></div>
<div class="content">
<button class="show-comments" id="content2"></button>
</div>
<div class="comments-wrapper" id="comment2"></div>
I have the following code:
$('.show-comments').click(function(e){
e.preventDefault();
$('.comments-wrapper').slideToggle('slow');
});
As you would assume, the code works but on a class basis. I'd like for it to open up only the .comments-wrapper of its associated id (i.e. open slideToggle comments2 if content 2 button is clicked and so on and so on).
How would I do this?

$('.show-comments').click(function(e){
e.preventDefault();
$(this).closest(".content").next('.comments-wrapper').slideToggle('slow');
});
Note that this is dependent on the .content element being immediately followed by the .comments-wrapper.
If you have access to modify the html itself, I would suggest adding a wrapper element and then doing the following to avoid the reliance on the exact order of elements:
<div class="wrapper">
<div class="content">
<button class="show-comments" id="content1"></button>
</div>
<div class="comments-wrapper" id="comment1"></div>
</div>
<div class="wrapper">
<div class="content">
<button class="show-comments" id="content2"></button>
</div>
<div class="comments-wrapper" id="comment2"></div>
</div>
$(this).closest(".wrapper").find('.comments-wrapper').slideToggle('slow');
This way, if you add an element between the .content and the .comments-wrapper it does not break the code.

You can do this:
$(this).parent("div").next('.comments-wrapper').slideToggle('slow');
This will find the related div of class .comments-wrapper and slide toggle.
And a fiddle: http://jsfiddle.net/xCJQB/

$('.show-comments').click(function (e) {
e.preventDefault();
var num = this.id.match(/\d+$/)[0];
$("#comment" + num).slideToggle('slow');
});
Demo ---> http://jsfiddle.net/7pkyk/1/

Use this context
$(this).closest('.comments').next('.comments-wrapper').slideToggle('slow');
If it is not the immediate element then you might try this as well
$(this).closest('.comments')
.nextAll('.comments-wrapper').first().slideToggle('slow');

you can add a common class to associate a button with a div.
html:
<div class="content">
<button class="show-comments group1" id="content1"></button>
</div>
<div class="comments-wrapper group1" id="comment1">1</div>
<div class="content">
<button class="show-comments group2" id="content2"></button>
</div>
<div class="comments-wrapper group2" id="comment2">2</div>
javascript:
$('.show-comments').click(function(e){
var associate = $(this).attr('class').match(/group\d+/).pop();
var selector = '.comments-wrapper.' + associate;
e.preventDefault();
$(selector).slideToggle('slow');
});
http://jsfiddle.net/uMNfJ/