#The Position Property
position property allows us to change the position of elements on our website. No big news, but depending on the value applied to this property, the element behaviour changes.
Not sure about that? Let's have a look behind the scenes of the
position property and its values in this article!
You prefer watching videos? Have a look at the video on top of this article!
#Why we need "position"
html elements follow a pre-defined behaviour - the document flow. Assuming that we have block-level elements only, this flow looks something like this:
If we want to position elements differently we need to change this behaviour. The
position property is not only able to tell elements to follow the default flow, it also allows us to deviate from it by adding three different values to it:
We also got
sticky, but due to limited browser (well, Internet Explorer...) compatibility we'll skip this one, at least in this article.
By applying one of these values, we can now change the default positioning of our elements, for example like this:Anything is possible as the `position` property can have an impact onto both the document flow and the so-called positioning context of an element. So let's dive into these now.
#Document Flow & Positioning Context
We already learned that
position allows us to position elements according to the document flow but also to take our elements out of this flow.
Additionally, we can also add these four properties to our CSS code once we added a value different from
static to our
With these properties we can move elements on our website, for example
top: 10px would move our element
10px down in relation to the
top of ... well of what actually?
We need a reference or a starting point to move our elements
10px down in relation to the
top of another element. The positioning context defines this starting point. Specifically the positioning context can be the viewport or any element on our website, depending on the applied value.
Let's keep that in mind and dive into the first value now,
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The orange area is the
body is yellow and the purple elements are
position: absolute takes an element out of the document flow, but how can we position the
Simply by adding
right to it. In our example we'll just add
top: 0 and
left: 0 and also remove any
margin from the element:
Whenever we add
position: absolute to an element, it is by default positioned relatively to the
html element which becomes the element's positioning context (note: This is only true if no parent element has a position property applied, more about that later in this article).
So in our example,
header has a distance of 0 pixels to the
top and to the
left of the
As a side note: We can also see that the
header no longer behaves like a block-level element but rather like an inline-block element. This also comes along with the
position: absolute declaration we applied, but won't affect our further understanding of the
Let's dive a bit deeper and also add
position: absolute to the
This happens, because adding the
position property with a value different than
static to a parent of an absolutely positioned element, will turn this parent element into the positioning context of the absolutely positioned element.
Long sentence in simple words: The closest positioned parent will become the reference point for the position of the absolutely positioned element.
Time to change
position: absolute to
position: relative on the
body element. As we can see on the screenshot, besides the fact that
body behaves like a block-level element again, nothing changed.
header is still positioned in relation to
Let's also add
top: 0px to
body as we previously did it for
header. Surprisingly nothing changes,
body doesn't move. Why?
Because the positioning context for an element with
position: relative is the element itself.
So in our example
top: 0px simply means "move the element from the top to the bottom by 0px, starting from the element's initial position (= the position according to the document flow)".
top: 50px moves the element down by 50px from top to bottom (or left to right for
Let's check that, by adding
top: 0px and remove the
But if we now scroll down (you might have to add
height: 1000px to the
html element to do so), we can see that
footer remains at its position no matter where we scroll to.
This happens because
fixed takes the document out of the document flow and changes the positioning context to the
viewport. And it always remains the viewport, even if we add
position: relative/absolute to a parent element.
With that we covered the core
position values. If you want to dive (a lot) deeper, we would be more than happy to welcome you on board of our 5-star rated CSS - The Complete Guide course.