We Keep Coding

Append class name to an iframe id that is included under a div class

I have the following code
<div id="ad">
<div id="adsensebanner">
<iframe id="google_ad_randomnumber">
</iframe>
</div>
</div>
and I'm searching of a way to make it like this, using jQuery and CSS attributes matching:
<div id="ad">
<div id="adsensebanner" class="addedclass">
<iframe id="google_ad_randomnumber">
</iframe>
</div>
</div>
Any ideas for searching for div that has another parent div and appending a class to the child one?

Your comments on various answers suggest your HTML is invalid and has more than one id="adsensebanner" in it, but just one id="ad" in it.
Your best bet is to make the HTML valid. There can be only one element with id="adsensebanner" in it.
However, if for some reason you want to only target that one element when it's inside id="ad":
document.querySelector("#ad #adsensebanner").classList.add("addedclass");
or with jQuery:
$("#ad #adsensebanner").addClass("addedclass");
That says "Add 'addedclass' to #adsensebanner only if it's inside #ad." There can be valid use-cases (if the one element with id="adsensebanner" may or may not be within #ad and you don't want to add the class if not), but they're rare.
If you correct the HTML to only have one id="adsensebanner", and you always want to add the class, then:
document.getElementById("adsensebanner").classList.add("addedclass");
or with jQuery:
$("#adsensebanner").addClass("addedclass");
In a comment you've said:
The double division check will definately work, however, my second div's ID name varies, so I would like to have it selected via an attr, like div[id*='adsensebanner']. Is there any workaround for this?
Yes, you can use any of the attribute substring selectors. For instance, if the id will always start with adsensebanner (id="adsensebanner1", id="adsensebanner2", etc.), then the selector to use with querySelector or jQuery would be "#ad div[id^=adsensebanner]". (Or you can use the contains one you mentioned, *=, or $= if it always ends with something.)

Try below:
$('#adsensebanner', window.parent.document).addClass("addedclass");

Simple JS can do the trick. And I can't see this div is inside the iFrame.
var p = document.getElementById("ad");
p.querySelector("[id='adsensebanner']").classList.add("addedClass");
<div id="ad">
<div id="adsensebanner">
<iframe id="google_ad_randomnumber">
</iframe>
</div>
</div>

This is only by JavaScript:
document.getElementById("ad").getElementsByTagName("div")[0].classList.add("addedClass");
$( "#ad div:nth-last-child(1)" ).addClass("addedClass");
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="ad">
<div id="adsensebanner">
<iframe id="google_ad_randomnumber">
</iframe>
</div>
</div>
<div id="ad1">
<div id="adsensebanner">
<iframe id="google_ad_randomnumber">
</iframe>
</div>
</div>
This will add a class only to div which have parent div id="ad"

How to remove div with a particular text in it

I have some div tags which has some text & elements in it & I want to remove those div's, They are looks like this
<div style="font-family:verdana;font-size:12px;">
Example
example
</div>
There are many div's like this & I want to remove them all with using jQuery or javascript

If the elements have nothing in common such as a class, you can remove it by using the :contains and remove() method.
$("div:contains('Example')").remove()
Full example shown below:
$("div:contains('Example')").remove()
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.0.3/jquery.min.js"></script>
<div>
Example
</div>
<div>
Darren
</div>
If the elements do have something in common you could use the class selector.
$(".common-class").remove();

Based on Darren's answer, if you want to be extra sure (as :contains will match and delete any div containing the word example), you can make sure it's a div that has an anchor with that same example as children, then go back to the parent and remove it.
If this doesn't work, please paste a few more divs so we can see a common pattern and target it the safest way possible.
$(document).ready(function(){
$('#remove').click(function(e){
$("div:contains('Example')").children("a:contains('example')").parent("div:contains('Example')").remove()
})
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div style="font-family:verdana;font-size:12px;">Example example</div>
<div style="font-family:verdana;font-size:12px;">Don't remove example</div>
<div style="font-family:verdana;font-size:12px;">Example don't remove</div>
<button id="remove">
Remove undesired divs
</button>

Add elements without removing existing content

I use jQuery .html() but is it possible to add an element without to removing the other HTML elements?
My code look so:
<div id="contentboxes">
<div class="con1">content 1</div>
<div class="con1">content 2</div>
</div>
I have tried this with jquery:
$('#contentboxes').html('<div class="con3">Content 3</div>');
But this command removes my other 2 boxes, is it possible to add without to removing other boxes?

use .append() instead of .html().

$('#contentboxes').append('<div class="con3">Content 3</div>');
http://api.jquery.com/append/

jquery custom data attribute not working inside div tag

I am using this div code
<div data-role="page" data-last-value="43" data-hidden="true" data-options='{"name":"John"}'></div>
and trying to print the values like
japp.init = function () {
console.log($("div").data("role"));
console.log($("div").data("lastValue"));
console.log($("div").data("hidden"));
console.log($("div").data("options").name);
});
This works fine if I put the above div tag directly inside body but as I put the div tag inside any other div tag it does not work and says undefined.
<div class="page">
<div data-role="page" data-last-value="43" data-hidden="true" data- options='{"name":"John"}'></div>
</div>
console prints undefined for above html.
Please let me know if anything is not clear

When getting data jQuery returns data from the first element matching selector, if the first div in DOM has no data - jquery won't return it.
try
japp.init = function () {
console.log($("div[data-role]").data("role"));
console.log($("div[data-lastValue]").data("lastValue"));
console.log($("div[data-hidden]").data("hidden"));
console.log($("div[data-options]").data("options").name);
});
or better give this div an id, and select by id like $('#someid').data('role')

Your selector is div and when you have more divs on your page jQuery will select (in this case) the first one.
<div class="page">
<div data-role="page" data-last-value="43" data-hidden="true" data- options='{"name":"John"}'></div>
</div>
In the above HTML the first div does not have data-* so it will result with an undefined value
You have to be more specific with your selectors
$('.page div').data('role')
Or
$('div:first div').data('role')

Try
$("div.page div").each(function(){
console.log($(this).data("whatever_you_need"));
});
etc.
This way you will cycle through all divs nested in div with class 'page'.

You aren't exactly specifying which div to get. Whenever you are trying to get specific data from a specific element, you should be sure which div you are accessing. This can either occur within an iteration of elements or by ID or an element in relation to an ID. It shouldn't be done based on tagname or even classname as they can be multiple. In this case, why not add an ID on the div you are trying to get so you can access it specifically:
<div class="page">
<div id="thisDiv" data-role="page" data-last-value="43" data-hidden="true" data- options='{"name":"John"}'></div>
</div>
Then access:
console.log($("#thisDiv").data("role"));
Also, it is bad for performance to wrap the same jquery object over and over, you can cache it like this:
$thisDiv = $("#thisDiv");
console.log($thisDiv.data("role"));
....

I believe it is because $("div") returns all occurrences of div and then selects the first to perform a function on. I'm not sure how you want to use this functionality but it might be worth considering something like this
JSFiddle where a class is used to select the correct div
$(function(){
console.log($(".div").data("role"));
console.log($(".div").data("lastValue"));
console.log($(".div").data("hidden"));
console.log($(".div").data("options").name);
});

give your Div a class like class="myClass"
<div class="page">
<div class="myClass" data-role="page" data-last-value="43" data-hidden="true" data- options='{"name":"John"}'></div>
</div>
and then you can change your jquery selector:
japp.init = function () {
console.log($(".myClass").data("role"));
console.log($(".myClass").data("lastValue"));
console.log($(".myClass").data("hidden"));
console.log($(".myClass").data("options").name);
});
otherwise jquery don't know which div you are looking for.
I hope this will help

jQuery: get a reference to a specific element without using id

I'm tinkering a bit with jquery to show a hidden div when a link is clicked. This should be fairly simple, but there's a flaw to it in this case. I have the following markup:
<div class="first-row">
<div class="week">
<p>Uge 2</p>
<p>(08-01-11)</p>
</div>
<div class="destination">
<p>Les Menuires</p>
<p>(Frankrig)</p>
</div>
<div class="days">4</div>
<div class="transport">Bil</div>
<div class="lift-card">3 dage</div>
<div class="accommodation">
<p><a class="show-info" href="#">Hotel Christelles (halvpension)</a></p>
<p>4-pers. værelse m. bad/toilet</p>
</div>
<div class="order">
<p>2149,-</p>
<p class="old-price">2249,-</p>
</div>
<div class="hotel-info">
<!-- The div I want to display on click -->
</div>
</div>
When I click the "show-info" link I want the "hotel-info" div to display.
My backend devs don't want me to use ids (don't ask me why..) and the above markup is used over and over again to display data. Therefore I need to be able to access the "hotel-info" div in the "first-row" div where the link is clicked.
I've tried to do something like:
$(document).ready(function() {
$('.show-info').click(function() {
var parentElement = $(this).parent().parent();
var lastElementOfParent = parentElement.find(".show-hotel");
lastElementOfParent.show();
});
});
But without a result :-/ Is this possible at all?
Any help is greatly appreciated!
Thanks a lot in advance!

Try this:
$('.show-info').click(function() {
$(this).closest('.accommodation').siblings('.hotel-info').show();
});
Even better imo, as it would be independent from where the link is in a row, if every "row div" has the same class (I assume only the first one has class first-row), you can do:
$(this).closest('.row-class').find('.hotel-info').show();
Reference: .closest, .siblings
Explanation why your code does not work:
$(this).parent().parent();
gives you the div with class .accommodation and this one has no descendant with class .hotel-info.
It is not a good idea to use this kind of traversal for more than one level anyway. If the structure is changed a bit, your code will break. Always try to use methods that won't break on structure changes.

You're right in not using an ID element to find the DIV you want :)
Use closest and nextAll
Live demo here : http://jsfiddle.net/jomanlk/xTWzn/
$('.show-info').click(function(){
$(this).closest('.accommodation').nextAll('.hotel-info').toggle();
});