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Enclose whole div in an <a>

I have a div which I want to surround with an <a href>. I have the jQuery to add the <a href> after the div but I struggle to set it before and close it after the div.
This is the jQuery code I have:
$('.box_service').each(function() {
var link = $(this).html();
$(this).contents().wrap('');
});
It results in this HTML:
<div class="row">
<div class="box_service">
<a href="example.com">
<div class="inner-row"></div>
</a>
</div>
</div>
However my goal is this structure:
<div class="row">
<a href="example.com">
<div class="box_service">
<div class="inner-row"></div>
</div>
</a>
</div>
I can't enter the div before because there are more boxes in this row so I would add the <a href> to everything in there

The issue is due to your call to contents() which means you're wrapping the elements inside .box_service, not that element itself. Remove that method call.
Also note that each() is redundant, you can do what you require in a single line:
$('.box_service').wrap('');
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="row">
<div class="box_service">
Box service #1
<div class="inner-row">Inner row #1</div>
</div>
</div>
<div class="row">
<div class="box_service">
Box service #2
<div class="inner-row">Inner row #2</div>
</div>
</div>

.content will wrap the contents of your div, you want to wrap the div with <a> so call wrap on the div not on contents.
$('.box_service').each(function() {
var link = $(this).html();
$(this).wrap('');
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="row">
<div class="box_service">
<div class="inner-row"></div>
</div>
</div>

$('.box_service').each(function() {
var link = $(this).html();
$(this).wrap('');
});
You just need to remove contents() in between $(this).wrap() because contents() mean that you are wrapping the children of $(this).

Remove .contents() in order to wrap around each element with the class box-service:
$('.box_service').each(function() {
$(this).wrap('');
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="row">
<div class="box_service">
<a href="example.com">
<div class="inner-row"></div>
</a>
</div>
</div>

$('.box_service').wrap('');

Switch Content of Div onclick

I've got two divs - each with one image inside. If I click on the image inside the second div I want this image to become the content of the first div (like a gallery).
It's important that I don't replace the links inside the img tag, so document.IMG1name.src=document.IMG2name.src isn't a possibility.
I tried it with innerhtml, but it doesnt work:
<div id="container1">
<img src="blablabla">
</div>
<div id="container2"; onclick="document.getElementById('container1').innerHTML=document.getElementById('container2').innerHTML"><img src="../funnycat.jpg">
</div>

mm... your code works fine, just close img tags and remove semicolon:
<div id="container1">
<img src="blablabla" />
</div>
<div id="container2" onclick="document.getElementById('container1').innerHTML=document.getElementById('container2').innerHTML"><img src="https://www.google.es/logos/doodles/2013/holiday-series-2013-3-4504416610680832-hp.jpg" />
</div>
here you have a demo: http://jsfiddle.net/HLs86/

HTML
<div class="pricing_table" id="monthly">
<ul>
<li>Basic</li>
<li>Subscribe Now</li>
</ul>
<ul style="background-color:#CCCCCC;">
<h2>Monthly Plans</h2><a class='plansSwitch' href='#yearly'>Click here to switch to the "Yearly Plans"</a></ul>
</div>
<div class="pricing_table" id="yearly">
<ul>
<li>Basic</li>
<li>Subscribe Now</li>
</ul>
<ul style="background-color:#CCCCCC;">
<h2>Yearly Plans</h2><a class='plansSwitch' href='#monthly'>Click here to switch to the "Monthly Plans"</a></ul>
</div>
JS
var $plansHolders = $('#monthly, #yearly').hide();
$('#monthly').show();
$('.plansSwitch').click(function() {
var href = $(this).attr('href');
$plansHolders.hide();
$(href).show();
});

you just need to add javascript: on your onclick action like this
<div id="container1"></div>
<div id="container2" onclick="javascript:document.getElementById('container1').innerHTML=document.getElementById('container2').innerHTML"><img src="http://i.imgur.com/0fS8dCsb.jpg"/>
</div>
there is example

Is there a way to wrapAll() but ignore one element?

If you have the following code:
<div class="parent">
<div class="1"></div>
<div class="2"></div>
<div class="3"></div>
<div class="4"></div>
<div class="5"></div>
</div>
How can I wrap a new div around div with class 2,3,4,5 so it looks like this:
<div class="parent">
<div class="1"></div>
<div class="sub">
<div class="2"></div>
<div class="3"></div>
<div class="4"></div>
<div class="5"></div>
</div>
</div>
wrapAll on the parent would wrap everything with a new div, is there a way to make it ignore the first div?

Use gt(0) to select all but the first one div(direct descendant) and wrapAll. This will select all divs with index greater than 0 present under .parent div.
$('.parent > div:gt(0)').wrapAll('<div class="sub">');
Fiddle
See :gt()
Output:
<div class="parent">
<div class="1">1</div>
<div class="sub">
<div class="2">2</div>
<div class="3">3</div>
<div class="4">4</div>
<div class="5">5</div>
</div>
</div>

Use the not() filter or the :not() selector.
$('.parent div').not('.1').wrapAll('<div class="sub">');
Or alternatively:
$('.parent div:not(.1)').wrapAll('<div class="sub">');
You can also use div:first-child in place of .1 if you always want to ignore the first element.

If the element you want to keep out is not necessarily the first, you could use:
$(".parent div").not("div.1").wrapAll("<div class='sub'>");
Although, this will re-order your divs so that the wrap comes first, and the unwrapped element comes last. Not a problem when it's the first element, but if it's the third, for example, the output would be:
<div class='sub'>
<div class="1"></div>
<div class="2"></div>
<div class="4"></div>
<div class="5"></div>
</div>
<div class="3"></div>
Example:
http://jsfiddle.net/tomtheman5/3TL4M/
edit: Just saw #Corion's answer... This is essentially the same, but with some more information. I'll leave it up.

How i can select specific div from multiple divs in jquery

I have something like this, and i need to show every div called "plink" just in the main div of each parent, so i tried to fadeIn ".plink" but its doing the same function for all the divs of "plink"
<script>
$(document).ready(function(){
$('.plink').hide();
$('.project').mouseover(function(){
$(this).next('.plink').fadeIn(400);
});
$('.project').mouseleave(function(){
$(this).next('.plink').fadeOut(200);
});
});
</script>
<div class="project">
<div class="plink">
<div class="go"></div>
<div class="goplus"><img src="images/more.png" border="0"/></div>
</div>
<div class="pic"><img src="images/portfolio_pic2.png" border="0" alt="projectname"/></div>
<div class="title">Test1</div>
</div>
<div class="spacer_project"></div>
<div class="project">
<div class="plink">
<div class="go"></div>
<div class="goplus"><img src="images/more.png" border="0"/></div>
</div>
<div class="pic"><img src="images/portfolio_pic.png" border="0" alt="projectname"/></div>
<div class="title">test2</div>
</div>

You can use find() instead of next()...
$(this).find('.plink').fadeIn(400);
because this is your .project div then you need to "find" the child elements that you are looking for. Using next() means you will get the very next element if it matches the selector (i.e. it is check to see if the next .project div matches the .plink selector)

I would go the FIND route like musefan suggested. Here is the solution code:
http://jsfiddle.net/bx7YC/
<div class="project">
<div class="plink">
<div class="go">go</div>
<div class="goplus">goplus</div>
</div>
<div class="pic">pic</div>
<div class="title">Test1</div>
</div>
<div class="spacer_project"></div>
<div class="project">
<div class="plink">
<div class="go">go</div>
<div class="goplus">goplus</div>
</div>
<div class="pic">pic</div>
<div class="title">Test2</div>
</div>​
$('.plink').hide();
$('.project').mouseover(function(){
$(this).find('.plink').fadeIn(400);
});
$('.project').mouseleave(function(){
$(this).find('.plink').fadeOut(200);
});​
I replaced the broken img links with simple text for the jsfiddle.

jQuery: Wrap only first and second child, not the rest of children

In my actual code:
<div id="mother">
<div id="child-01"></div>
<div id="child-02"></div>
<div id="child-03"></div>
</ul>
I need to produce:
<div id="mother">
<div id="myWrap">
<div id="child-01"></div>
<div id="child-02"></div>
</div>
<div id="child-03"></div>
</ul>
I was playing with wrap, .wrapAll() and children, but I'm stuck.
If in my actual code i have:
<div id="mother">
<div id="child-01"></div>
<div id="child-02"></div>
<div id="child-03"></div>
</ul>
<div id="uncle">
<div id="cousin-01"></div>
<div id="cousin-02"></div>
<div id="cousin-03"></div>
</ul>
How do i produce:
<div id="mother">
<div id="myWrap">
<div id="child-01"></div>
<div id="child-02"></div>
<div id="cousin-02"></div>
</div>
<div id="child-03"></div>
</ul>

First as Adam said remove the # prefix from your id attributes. Also match your closing tags, currently you have a </ul> where a </div> should be.
Then, you can do it using :lt() and .wrapAll() like this:
$("#mother div:lt(2)").wrapAll("<div id='myWrap'></div>");
This gets everything less than index 2 (0 and 1 are the first 2), then wraps it. You can test it here.

Remove # from your HTML ids.
$("#mother div:eq(0), #mother div:eq(1)").wrapAll("<div id='father'></div>")

sharp should not be part of the id's. Then you can do:
$('#child-01, #child-02').wrapAll('<div id="#mywrap" />');

$(document).ready(function(){
$(".new-grid__item:nth-child(1), .new-grid__item:nth-child(2)").wrapAll('<div class="child"></div>');
});