CSS Float and Clear

Clear

Float

CSS allows you to 'wrap' an element around other. You can do this with the float property.
This property shifts an item horizontally, left or right from its original placement, leaving a blank space in the opposite direction, which will be filled by the next HTML element. But the elements before the floating element will not be affected.
A floated element will move as far to the left or right as it can. Usually this means all the way to the left or right of the containing parent.
If you place several floating elements after each other, they will float next to each other if there is room.

- Values:

none - The element is not floated and behaves as normal (default).
left - The element is taken out of the normal flow and is shifted to the left of where it was, with content flowing around it on the right side of the element.
right - The element is taken out of the normal flow and is shifted to the right of where it was, with content flowing around it on the left side of the element.

- Syntax:

selector { float: value; }

- Example (Two <div> tags, first with float:right, the second with float:left, and a text content after them).
The first DIV is pushed to the right, leaving a blank space to its left. The second div is pushed to the left in that space, leaving another empty space in its right side, that will be filled by the next item, if fits (here a text content).

<style>
#dv1 {
width: 200px;
float: right;
border: 2px solid green;
}
#dv2 {
width: 200px;
float: left;
border: 2px solid blue;
}
</style>

<h4>Example float</h4>
<div id='dv1'>DIV 1, with float: right;</div>
<div id='dv2'>DIV 2, with float: left;</div>
Text content after the floated DIVs.

Absolutely positioned elements ignores the float property.

Clear

The clear property has an action similar to <br> HTML tag that moves to a new row the next element.
When an element is floated it leaves an empty space in the oposite direction. With the 'clear' property can be avoided the filling of that blank space by the next item.
The clear property is used to insert a break when encountering a new section of the layout to stop the wrapping effect. It specifies which sides of an element other floating elements are not allowed.

- Values:

none - The element does not clear any floats (default).
left - The element will be shifted down to sufficiently clear the bottom edge of any previous left-floated elements.
right - The element will be shifted down to sufficiently clear the bottom edge of any previous right-floated elements.
both - Clears and begin a new line after all floated elements.

- Syntax:

selector { clear: value; }

- Example (A new version of the example above, here is added the clear:right in the '#dv2' selector and a <br> tag with clear:both before the text content):

<style>
#dv1 {
width: 200px;
float: right;
border: 2px solid green;
}
#dv2 {
clear: right;
width: 200px;
float: left;
border: 2px solid blue;
}
</style>

<h4>Example CSS clear</h4>
<div id='dv1'>DIV 1, with float: right;</div>
<div id='dv2'>DIV 2, with float: left;</div>
<br style='clear:both'>
Text content after the floated DIVs.

<<-Positioning -- Pseudo-classes->>

Daily Test with Code Example

HTML

CSS

JavaScript

PHP-MySQL

Which tag is used to add lists into <ul> and <ol> elements?

<ul>
 <li>http://coursesweb.net/html/</li>
 <li>http://coursesweb.net/css/</li>
</ul>

Which value of the "display" property creates a block box for the content and ads a bullet marker?

block list-item inline-block

.some_class {
  display: list-item;
}

Which instruction converts a JavaScript object into a JSON string.

JSON.parse() JSON.stringify eval()

var obj = {
 "courses": ["php", "javascript", "ajax"]
};
var jsonstr = JSON.stringify(obj);
alert(jsonstr);    // {"courses":["php","javascript","ajax"]}

Indicate the PHP class used to work with HTML and XML content in PHP.

stdClass PDO DOMDocument

$strhtml = '<body><div id="dv1">CoursesWeb.net</div></body>';
$dochtml = new DOMDocument();
$dochtml->loadHTML($strhtml);
$elm = $dochtml->getElementById("dv1");
echo $elm->nodeValue;    // CoursesWeb.net