Animate an element's width from 0 to 100%, with it and it's wrapper being only as wide as they need to be, without a pre-set width, in CSS3 or jQuery

Jquery Problem Overview

http://jsfiddle.net/nicktheandroid/tVHYg/

When hovering .wrapper, it's child element .contents should animate from 0px to it's natural width. Then when the mouse is removed from .wrapper, it should animate back down to 0px. The .wrapper element should only be as wide as it needs to be (allowing .contents to grow), so .wrapper should grow in width and shrink in width as .contents does. There should be no set width for .contents. I'm using CSS3, but it could be accomplished in jQuery, that would be fine.

The problem: See the JSfiddle

.wrapper is not only as wide as it needs to be.
when .contents grows, when it's almost at it's full width, it jumps down to the next line
When hovering off of .wrapper, .contents vanishes, when it should animate down to 0px

.wrapper {
    display: inline-block;

    height: 20px;
    width: auto;
  
    padding:10px;
  
    background:#DDD;
}

.contents {
    display:inline-block;
  
    width:0%;
  
    white-space:nowrap;
    overflow:hidden;
  
    background:#c3c;
}

.wrapper:hover .contents {
    -webkit-transition: width 1s ease-in-out;
    -moz-transition: width 1s ease-in-out;
    -o-transition: width 1s ease-in-out;
    transition: width 1s ease-in-out;

    width:100%;
}

<div class="wrapper">
    <span>+</span>
    <div class="contents">These are the contents of this div</div>
</div>

Jquery Solutions

Solution 1 - Jquery

I think I've got it.

.wrapper {
    background:#DDD;
    display:inline-block;
    padding: 10px;
    height: 20px;
    width:auto;
}

.label {
    display: inline-block;
    width: 1em;
}

.contents, .contents .inner {
    display:inline-block;
}

.contents {
    white-space:nowrap;
    margin-left: -1em;
    padding-left: 1em;
}

.contents .inner {
    background:#c3c;
    width:0%;
    overflow:hidden;
    -webkit-transition: width 1s ease-in-out;
    -moz-transition: width 1s ease-in-out;
    -o-transition: width 1s ease-in-out;
    transition: width 1s ease-in-out;
}



.wrapper:hover .contents .inner {
   
    width:100%;
}

<div class="wrapper">
    <span class="label">+</span>
    <div class="contents">
        <div class="inner">
            These are the contents of this div
        </div>
    </div>
</div>

Animating to 100% causes it to wrap because the box is bigger than the available width (100% minus the + and the whitespace following it).

Instead, you can animate an inner element, whose 100% is the total width of .contents.

Solution 2 - Jquery

http://jsfiddle.net/tVHYg/5/

.wrapper {
    background:#DDD;
    padding:1%;
    display:inline;
    height:20px;
}


span {
    width: 1%;
}

.contents {
    background:#c3c;
    overflow:hidden;
    white-space:nowrap;
    display:inline-block;
    width:0%;
}



.wrapper:hover .contents {
    -webkit-transition: width 1s ease-in-out;
    -moz-transition: width 1s ease-in-out;
    -o-transition: width 1s ease-in-out;
    transition: width 1s ease-in-out;
   
    width:90%;
}

Solution 3 - Jquery

Got it to work by transitioning the padding as well as the width.

JSFiddle: http://jsfiddle.net/tuybk748/1/

<div class='label gray'>+
</div><!-- must be connected to prevent gap --><div class='contents-wrapper'>
	<div class="gray contents">These are the contents of this div</div>
</div>

.gray {
	background: #ddd;
}
.contents-wrapper, .label, .contents {
	display: inline-block;
}
.label, .contents {
	overflow: hidden; /* must be on both divs to prevent dropdown behavior */
	height: 20px;
}
.label {
	padding: 10px 10px 15px;
}
.contents {
	padding: 10px 0px 15px; /* no left-right padding at beginning */
	white-space: nowrap; /* keeps text all on same line */
	width: 0%;
	-webkit-transition: width 1s ease-in-out, padding-left 1s ease-in-out, 
        padding-right 1s ease-in-out;
	-moz-transition: width 1s ease-in-out, padding-left 1s ease-in-out, 
        padding-right 1s ease-in-out;
	-o-transition: width 1s ease-in-out, padding-left 1s ease-in-out, 
        padding-right 1s ease-in-out;
	transition: width 1s ease-in-out, padding-left 1s ease-in-out, 
        padding-right 1s ease-in-out;
}
.label:hover + .contents-wrapper .contents {
	width: 100%;
	padding-left: 10px;
	padding-right: 10px;
}

Solution 4 - Jquery

a late answer, but I think this one works as required in the question :)

this one uses z-index and position absolute, and avoid the issue that the container element width doesn't grow in transition.

You can tweak the text's margin and padding to suit your needs, and "+" can be changed to font awesome icons if needed.

body {
  font-size: 16px;
}

.container {
  height: 2.5rem;
  position: relative;
  width: auto;
  display: inline-flex;
  align-items: center;
}

.add {
  font-size: 1.5rem;
  color: #fff;
  cursor: pointer;
  font-size: 1.5rem;
  background: #2794A5;
  border-radius: 20px;
  height: 100%;
  width: 2.5rem;
  display: flex;
  justify-content: center;
  align-items: center;
  position: absolute;
  z-index: 2;
}

.text {
  white-space: nowrap;
  position: relative;
  z-index: 1;
  height: 100%;
  width: 0;
  color: #fff;
  overflow: hidden;
  transition: 0.3s all ease;
  background: #2794A5;
  height: 100%;
  display: flex;
  align-items: center;
  border-top-right-radius: 20px;
  border-bottom-right-radius: 20px;
  margin-left: 20px;
  padding-left: 20px;
  cursor: pointer;
}

.container:hover .text {
  width: 100%;
  padding-right: 20px;
}

<div class="container">
  <span class="add">+</span>
  <span class="text">Add new client</span>
</div>

Solution 5 - Jquery

Please check following snippet

 /* DEBUG */
.lwb-col {
    transition: box-shadow 0.5s ease;
}
.lwb-col:hover{
    box-shadow: 0 15px 30px -4px rgba(136, 155, 166, 0.4);
 
}


.lwb-col--link {
    font-weight: 500;
  position: relative;
  display: inline-block;
}
.lwb-col--link::after{
    border-bottom: 2px solid;
    bottom: -3px;
    content: "";
    display: block;
    left: 0;
    position: absolute;
    width: 100%;
    color: #E5E9EC;

}
.lwb-col--link::before{
    border-bottom: 2px solid;
    bottom: -3px;
    content: "";
    display: block;
    left: 0;
    position: absolute;
    width: 100%;
    color: #57B0FB;
    transform: scaleX(0);
    

}
.lwb-col:hover .lwb-col--link::before {
    border-color: #57B0FB;
    display: block;
    z-index: 2;
    transition: transform 0.3s;
    transform: scaleX(1);
    transform-origin: left center;
}

<div class="lwb-col">
  <h2>Webdesign</h2>
  <p>Steigern Sie Ihre Bekanntheit im Web mit individuellem &amp; professionellem Webdesign. Organisierte Codestruktur, sowie perfekte SEO Optimierung und jahrelange Erfahrung sprechen für uns.</p>
<span class="lwb-col--link">Mehr erfahren</span>
</div>

Solution 6 - Jquery

I haven't been able to get it to work without specifying a width but the following css worked

.wrapper {
    background: #DDD;
    padding: 10px;
    display: inline-block;
    height: 20px;
    width: auto;
}

.contents {
    background: #c3c;
    overflow: hidden;
    white-space: nowrap;
    display: inline-block;
    visibility: hidden;
    width: 1px;
    -webkit-transition: width 1s ease-in-out, visibility 1s linear;
    -moz-transition: width 1s ease-in-out, visibility 1s linear;
    -o-transition: width 1s ease-in-out, visibility 1s linear;
    transition: width 1s ease-in-out, visibility 1s linear;
}

.wrapper:hover .contents {
    width: 200px;
    visibility: visible;
}

I'm not sure you will be able to get it working without setting a width on it.

Content Type	Original Author	Original Content on Stackoverflow
Question	android.nick	View Question on Stackoverflow
Solution 1 - Jquery	eyelidlessness	View Answer on Stackoverflow
Solution 2 - Jquery	chovy	View Answer on Stackoverflow
Solution 3 - Jquery	Chris Middleton	View Answer on Stackoverflow
Solution 4 - Jquery	Roy.L.T	View Answer on Stackoverflow
Solution 5 - Jquery	tanvi korgaonkar	View Answer on Stackoverflow
Solution 6 - Jquery	Nalum	View Answer on Stackoverflow