How to place two divs next to each other?

Consider the following code:

<div id="wrapper">
    <div id="first">Stack Overflow is for professional and enthusiast programmers, people who write code because they love it.</div>
    <div id="second">When you post a new question, other users will almost immediately see it and try to provide good answers. This often happens in a matter of minutes, so be sure to check back frequently when your question is still new for the best response.</div>
</div>

#wrapper {
    width: 500px;
    border: 1px solid black;
}
#first {
    width: 300px;
    border: 1px solid red;
}
#second {
    border: 1px solid green;
}

I would like the two divs to be next to each other inside the wrapper div. In this case, the height of the green div should determine the height of the wrapper.

How could I achieve this via CSS ?

Float one or both inner divs.

Floating one div:

#wrapper {
    width: 500px;
    border: 1px solid black;
    overflow: hidden; /* will contain if #first is longer than #second */
}
#first {
    width: 300px;
	float:left; /* add this */
    border: 1px solid red;
}
#second {
    border: 1px solid green;
	overflow: hidden; /* if you don't want #second to wrap below #first */
}

or if you float both, you'll need to encourage the wrapper div to contain both the floated children, or it will think it's empty and not put the border around them

Floating both divs:

#wrapper {
    width: 500px;
    border: 1px solid black;
    overflow: hidden; /* add this to contain floated children */
}
#first {
    width: 300px;
    float:left; /* add this */
    border: 1px solid red;
}
#second {
    border: 1px solid green;
    float: left; /* add this */
}

Having two divs, you could also use the display property:

#wrapper {
    border: 1px solid blue;
}
#div1 {
    display: inline-block;
    width:120px;
    height:120px;
    border: 1px solid red;
}
#div2 {
    display: inline-block;
    width:160px;
    height:160px;
    border: 1px solid green;
}

<div id="wrapper">
    <div id="div1">The two divs are</div>
    <div id="div2">next to each other.</div>
</div>

If div1 exceeds a certain height, div2 will be placed next to div1 at the bottom. To solve this, use vertical-align:top; on div2.

#wrapper {
    border: 1px solid blue;
}
#div1 {
    display: inline-block;
    width:120px;
    height:120px;
    border: 1px solid red;
}
#div2 {
    vertical-align:top;
    display: inline-block;
    width:160px;
    height:160px;
    border: 1px solid green;
}

<div id="wrapper">
    <div id="div1">The two divs are<br/><br/><br/><br/><br/><br/></div>
    <div id="div2">next to each other.</div>
</div>

jsFiddle for example 1.

jsFiddle for example 2.

You can sit elements next to each other by using the CSS float property:

#first {
float: left;
}
#second {
float: left;
}

You'd need to make sure that the wrapper div allows for the floating in terms of width, and margins etc are set correctly.

Try to use flexbox model. It is easy and short to write.

Live Jsfiddle

CSS:

#wrapper {
  display: flex;
  border: 1px solid black;
}
#first {
    border: 1px solid red;
}
#second {
    border: 1px solid green;
}

default direction is row. So, it aligns next to each other inside the #wrapper. But it is not supported IE9 or less than that versions

Option 1

Use float:left on both div elements and set a % width for both div elements with a combined total width of 100%.

Use box-sizing: border-box; on the floating div elements. The value border-box forces the padding and borders into the width and height instead of expanding it.

Use clearfix on the <div id="wrapper"> to clear the floating child elements which will make the wrapper div scale to the correct height.

.clearfix:after {
   content: " "; 
   visibility: hidden;
   display: block;
   height: 0;
   clear: both;
}

#first, #second{
  box-sizing: border-box;
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
}

#wrapper {
    width: 500px;
    border: 1px solid black;
}
#first {
    border: 1px solid red;
    float:left;
    width:50%;
}
#second {
    border: 1px solid green;
    float:left;
    width:50%;
}

http://jsfiddle.net/dqC8t/3381/

Option 2

Use position:absolute on one element and a fixed width on the other element.

Add position:relative to <div id="wrapper"> element to make child elements absolutely position to the <div id="wrapper"> element.

#wrapper {
    width: 500px;
    border: 1px solid black;
    position:relative;
}
#first {
    border: 1px solid red;
    width:100px;
}
#second {
    border: 1px solid green;
    position:absolute;
    top:0;
    left:100px;
    right:0;
}

http://jsfiddle.net/dqC8t/3382/

Option 3

Use display:inline-block on both div elements and set a % width for both div elements with a combined total width of 100%.

And again (same as float:left example) use box-sizing: border-box; on the div elements. The value border-box forces the padding and borders into the width and height instead of expanding it.

NOTE: inline-block elements can have spacing issues as it is affected by spaces in HTML markup. More information here: https://css-tricks.com/fighting-the-space-between-inline-block-elements/

#first, #second{
  box-sizing: border-box;
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
}

#wrapper {
    width: 500px;
    border: 1px solid black;
    position:relative;
}

#first {
    width:50%;
    border: 1px solid red;
    display:inline-block;
}

#second {
    width:50%;
    border: 1px solid green;
    display:inline-block;
}

http://jsfiddle.net/dqC8t/3383/

A final option would be to use the new display option named flex, but note that browser compatibility might come in to play:

http://caniuse.com/#feat=flexbox

http://www.sketchingwithcss.com/samplechapter/cheatsheet.html

here is the solution:

#wrapper {
    width: 500px;
    border: 1px solid black;
    overflow: auto; /* so the size of the wrapper is alway the size of the longest content */
}
#first {
    float: left;
    width: 300px;
    border: 1px solid red;
}
#second {
    border: 1px solid green;
    margin: 0 0 0 302px; /* considering the border you need to use a margin so the content does not float under the first div*/
}

your demo updated;

http://jsfiddle.net/dqC8t/1/

It is very easy - you could do it the hard way

.clearfix:after {
   content: " "; 
   visibility: hidden;
   display: block;
   height: 0;
   clear: both;
}

#first, #second{
  box-sizing: border-box;
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
}

#wrapper {
    width: 500px;
    border: 1px solid black;
}
#first {
    border: 1px solid red;
    float:left;
    width:50%;
}
#second {
    border: 1px solid green;
    float:left;
    width:50%;
}

<div id="first">Stack Overflow is for professional and enthusiast programmers, people who write code because they love it.</div>
    <div id="second">When you post a new question, other users will almost immediately see it and try to provide good answers. This often happens in a matter of minutes, so be sure to check back frequently when your question is still new for the best response.</div>
</div>

or the easy way

#wrapper {
  display: flex;
  border: 1px solid black;
}
#first {
    border: 1px solid red;
}
#second {
    border: 1px solid green;
}

<div id="wrapper">
    <div id="first">Stack Overflow is for professional and enthusiast programmers, people who write code because they love it.</div>
    <div id="second">When you post a new question, other users will almost immediately see it and try to provide good answers. This often happens in a matter of minutes, so be sure to check back frequently when your question is still new for the best response.</div>
</div>

There's also like a million other ways.
But I'd just with the easy way. I would also like to tell you that a lot of the answers here are incorrect But both the ways that I have shown at least work in HTML 5.

Try to use below code changes to place two divs in front of each other

#wrapper {
  width: 500px;
  border: 1px solid black;
  display:flex;
}

JSFiddle link

This is the right CSS3 answer. Hope this helps you somehow now :D I really recommend you to read the book: https://www.amazon.com/Book-CSS3-Developers-Future-Design/dp/1593272863 Actually I have made this solution from reading this book now. :D

#wrapper{
  display: flex;
  flex-direction: row;
  border: 1px solid black;
}
#first{
  width: 300px;
  border: 1px solid red;
}
#second{
  border: 1px solid green;
}

<div id="wrapper">
    <div id="first">Stack Overflow is for professional and enthusiast programmers, people who write code because they love it.</div>
    <div id="second">When you post a new question, other users will almost immediately see it and try to provide good answers. This often happens in a matter of minutes, so be sure to check back frequently when your question is still new for the best response.</div>
</div>

1. Add float:left; property in both divs.

2. Add display:inline-block; property.

3. Add display:flex; property in parent div.

My approach:

<div class="left">Left</div>
<div class="right">Right</div>

CSS:

.left {
    float: left;
    width: calc(100% - 200px);
    background: green;
}

.right {
    float: right;
    width: 200px;
    background: yellow;
}

In material UI and react.js you can use the grid

<Grid
  container
  direction="row"
  justify="center"
  alignItems="center"
>
    <Grid item xs>
      <Paper className={classes.paper}>xs</Paper>
    </Grid>
    <Grid item xs>
      <Paper className={classes.paper}>xs</Paper>
    </Grid>
    <Grid item xs>
      <Paper className={classes.paper}>xs</Paper>
    </Grid>

</Grid>

#wrapper {
width: 1200;
border: 1px solid black;
position: relative;
float: left;
}
#first {
width: 300px;
border: 1px solid red;
position: relative;
float: left;
}
#second {
border: 1px solid green;
position: relative;
float: left;
width: 500px;
}

<div id="wrapper">
    <div id="first">Stack Overflow is for professional and enthusiast programmers, people who write code because they love it.</div>
    <div id="second">When you post a new question, other users will almost immediately see it and try to provide good answers. This often happens in a matter of minutes, so be sure to check back frequently when your question is still new for the best response.</div>
</div>