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Mis à jour le 13/03/2023

Add custom borders to elements

Much like you can frame a picture and hang it on your wall, you can add borders to your HTML elements that frame them visually.

This element has an orange border, for example:

Element with an orange border
Element with an orange border

There are many different ways to adapt a border's style! Here are just some examples of what web borders in CSS might look like (you'll see all of them in this chapter!):

So many border options!
So many border options!

In CSS, you can control a border's:

  • width (thin, wide, 5px, etc.)

  • style (solid, dashed, etc.)

  • color (hex code, RGB value, etc.)

This results in a ton of border options that can spice up your elements.

You can also create borders around elements in either a shorthand or longhand way, depending on your preference. We'll explore how to do both in this chapter!

Border syntax

Before we look at border value examples, there are two general ways to set borders:

  • a longhand way where you list out each value in a different property (ex.  border-width  ,  border-style  , and  border-color  ).

  • a shorthand way where you combine all values into one property called border

Let's look at the shorthand way first. You can set borders in CSS using one simple property called border. In it, you will specify three border properties in the following order:

  • width

  • style

  • color

Here are three quick examples of setting borders using the shorthand method:

h1 {
    border: 5px solid red;
}

h3 {
    border: 1em dashed #A4036F;
}

p {
    border: thick dotted rgb(22, 219, 147);
}

You can also set borders the longhand way by specifying all border values as different properties. Here are the same three examples from above, written out the longhand way:

h1 {
    border-width: 5px;
    border-style: solid; 
    border-color: red;
}

h3 {
    border-width: 1em;
    border-style: dashed; 
    border-color: #A4036F;
}

p {
    border-width: thick;
    border-style: dotted;
    border-color: rgb(22, 219, 147);
}

You'll often set borders the shorthand way because it's faster and more concise. In the below sections, though, we'll write each property out the longhand way for the sake of clarity.

Setting border width

Border widths can be set as either pixel values, em/rem values, or using a word that CSS has already pre-defined, like "thin," "medium," or "thick."

As you saw above, the width will be the first value in the shorthand way to specify borders. However, it can also be set on its own with the  border-width  property.

I most often set borders using pixels, but you could also use em/rem in order to keep the border width proportional to the text. If an element has a font-size of16px, setting a border width of 1em means the border will be 16px wide. If a user has their font preferences set to a higher size, though, and you set your border size in em/rem, your border will grow or shrink accordingly (which would not happen with a pixel value).

Thin, medium, and thick borders
Different border widths
p {
    border-width: thin;
}

p {
    border-width: medium;
}

p {
    border-width: thick;
}

p {
    border-width: 8px;
}

p {
    border-width: 1.5em;
}

Setting border style

In reality, you'll most often specify a "solid" border style. Depending on a certain style you're going for, though, you might choose a different border aesthetic. Here is the full list of possible options for setting borders in CSS:

  • solid

  • dashed

  • dotted

  • double

  • groove

  • hidden

  • none

  • ridge

  • inset

  • outset

The following image represents each border style, except "hidden." Based on the list above, guess which border style corresponds to each image below.  Check the CSS code following the image to find out if you're right:

All possible border styles
All possible border styles
p {
    border-style: solid;
}

p {
    border-style: dashed;
}

p {
    border-style: dotted;
}

p {
    border-style: double;
}

p {
    border-style: groove;
}

p {
    border-style: none;
}

p {
    border-style: ridge;
}

p {
    border-style: inset;
}

p {
    border-style: outset;
}

You can even set specific border styles per side by using property names that specify the top, bottom, left, or right border:

p {
    border-top-style: dotted;
    border-bottom-style: dashed;
    border-left-style: solid;
    border-right-style: double;
}

This usually looks a little goofy, though:

Different border styles per side
Different border styles per side

Setting border color

Set border colors the same way you set most colors in CSS, using:

  • hex codes

  • RGB or RGBA values

  • color names

  • hsl values

If you're not sure about how to set these colors, check out this chapter on color theory from our introductory HTML and CSS course. 

Like we saw with border style, you can even set a different border color per side by specifying whether you're talking about the top, bottom, right, or left border color.

p {
    border-top-color: #16DB93;
    border-bottom-color: #A4036F;
    border-left-color: #EFEA5A;
    border-right-color: #FE5E41;
}

The result looks like this:

Different border colors per side
Different border colors per side

Setting border radius

Lastly, you can also set rounded borders by using a property called  border-radius  using em/rem values, pixels, or percentages:

p {
    border-radius: 5px;
}
Rounded corners via border radius
Rounded corners via border radius

Despite all the fancy things you can do with borders, I advise you to keep your borders simple so that users can focus on the content itself.

Now, you may be wondering how to set additional space in between text and its borders. This often gives elements more room to breathe. Compare the left and right texts to see the difference:

Preview of padding, the subject of our next chapter
Preview of padding, the subject of our next chapter

This space is set using a different CSS property we'll see in the next chapter called padding. In the meantime, how about an interactive exercise? 👍

Your Turn

It's your turn to modify the code in this CodePen. Add a different border style, color, and width to each of the paragraph elements. One has already been done for you, but you can change it!

Recap

  • Each HTML element has a border.

  • To set the width of a border, use  border-width  and define the size with pixels, em/rem, or special CSS words (thin, medium, thick).

  • To set the style, use  border-style  and choose a style from the list of available CSS words.  

  • To set the color, use  border-color  and use either hex, RGB, or RGBA color codes. 

  • To set width, style, and color all at once, use the  border  property.

  • To set individual borders, use top, right, left, and bottom (ex.  border-top-style ).

  • To curve the corners of a border, use  border-radius  .

Exemple de certificat de réussite
Exemple de certificat de réussite