rick@tillitsdone.com

+66824564755

Scroll to discover

Enhance Text Readability with CSS text-underline-position

CSS text-underline-position allows you to control the exact position of text underlines, enhancing readability and aesthetics.

Available options include auto, under, left, and right, providing flexibility for various web design scenarios.

Introduction

The text-underline-position CSS property lets you control exactly where the underline appears on your text. It works with the text-decoration property’s underline value. By using text-underline-position, you can make your text more readable and visually appealing, which is great for complex layouts and designs.

Specification

The text-underline-position property is defined in the CSS Text Decoration Module Level 3 specification. This module gives detailed guidelines on how text decorations, including underlines, should be handled in web browsers. The specification ensures consistency across different browsers, making it easier for you to create uniform and predictable text decorations.

Syntax

The text-underline-position property is easy to use. Here’s the syntax for specifying the underline position relative to the text:

/* Single keyword */
text-underline-position: auto;
text-underline-position: under;
text-underline-position: left;
text-underline-position: right;

/* Multiple keywords */
text-underline-position: under left;
text-underline-position: right under;

/* Global values */
text-underline-position: inherit;
text-underline-position: initial;
text-underline-position: revert;
text-underline-position: revert-layer;
text-underline-position: unset;

Values

The text-underline-position property offers several values to fine-tune the underline’s position:

`auto`

The auto value lets the browser decide the best position for the underline based on the font metrics.

`from-font`

If the font file includes a preferred underline position, the from-font value uses that information. If not, it behaves like auto.

`under`

The under value puts the underline below the alphabetic baseline, ensuring it doesn’t cross any descenders. This is great for enhancing text readability.

`left`

In vertical writing modes, the left value puts the underline on the left side of the text. In horizontal modes, it behaves like auto.

`right`

Similar to left, the right value puts the underline on the right side of the text in vertical writing modes. In horizontal modes, it behaves like auto.

Inheritance and Global Values

inherit: Makes the element inherit the text-underline-position value from its parent.
initial: Resets the property to its initial value, which is auto.
revert: Reverts the property to the browser’s default styling.
revert-layer: Similar to revert, but it only reverts the property for the current cascade layer.
unset: Resets the property to its natural value, which means it acts as inherit if the property is inherited, or initial if it is not.

Formal Definition

Here are the key aspects of the text-underline-position property’s formal definition:

Attribute	Value
Initial Value	`auto`
Applies to	All elements
Inherited	Yes
Computed Value	As specified
Animation Type	Discrete

Formal Syntax

The formal syntax for the text-underline-position property is:

text-underline-position =
  auto                           /* Single keyword */
  [ under || left || right ]      /* Multiple keywords */

Examples

Let’s look at some practical examples to see how the text-underline-position property works.

Example 1: Basic Usage

Here, we’ll use the text-underline-position: auto and text-underline-position: under properties to see the differences.

HTML:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>CSS text-underline-position Property</title>
    <style>
        p {
            width: 20rem;
        }
        .first {
            text-decoration: underline;
            text-underline-position: auto;
        }
        .second {
            text-decoration: underline;
            text-underline-position: under;
        }
    </style>
</head>
<body>
    <h1 style="color:green;">Website</h1>
    <h3>text-underline-position: auto;</h3>
    <p class="first">
        A Computer Science portal for geeks. It contains well written, well thought and well explained computer science and programming articles.
    </p>
    <h3>text-underline-position: under;</h3>
    <p class="second">
        We provide a variety of services for you to learn, thrive and also have fun!
    </p>
</body>
</html>

Output:

![Example 1 Output]WebsiteUrl

In this example, text-underline-position: auto uses the browser’s default positioning for the underline, while text-underline-position: under ensures the underline is placed below the alphabetic baseline, avoiding any descenders.

Example 2: Vertical Writing Mode

Here, we’ll use the writing-mode: vertical-rl property to write text vertically. We’ll then apply text-underline-position: left and text-underline-position: right to see their effects.

HTML:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>CSS text-underline-position Property</title>
    <style>
        p {
            height: 20rem;
            padding: 1rem;
        }
        div {
            display: flex;
        }
        .first {
            text-decoration: underline;
            writing-mode: vertical-lr;
            text-underline-position: left;
            background-color: rgba(95, 158, 160, 0.602);
        }
        .second {
            text-decoration: underline;
            writing-mode: vertical-lr;
            text-underline-position: right;
            background-color: rgba(255, 127, 80, 0.49);
        }
    </style>
</head>
<body>
    <h1 style="color:green;">Website</h1>
    <div>
        <h3>text-underline-position: left;</h3>
        <p class="first">
            A Computer Science portal for geeks. It contains well written, well thought and well explained computer science and programming articles.
        </p>
        <h3>text-underline-position: right;</h3>
        <p class="second">
            We provide a variety of services for you to learn, thrive and also have fun!
        </p>
    </div>
</body>
</html>

Output:

![Example 2 Output]WebsiteUrl

In this example, text-underline-position: left places the underline on the left side of the vertically written text, while text-underline-position: right places it on the right side. This is useful for languages that are written vertically, like Japanese or Chinese.

Setting `text-underline-position` Globally

You can set the text-underline-position property globally to ensure consistent underlining styles throughout your website. This is great for documents with specific needs, like those with lots of chemical or mathematical formulas.

CSS:

:root {
  text-underline-position: under;
}

By setting the text-underline-position property at the root level, you apply a uniform underline position to all text elements on your page. This simplifies your CSS and ensures that all underlines are consistently styled, enhancing the overall readability and visual appeal of your content.

Browser Compatibility

The text-underline-position property is widely supported by modern web browsers. However, it’s always a good idea to test your web pages across different browsers to ensure consistent behavior.

Browser Compatibility

The text-underline-position property is widely supported by modern browsers:

Google Chrome: Yes
Microsoft Edge: Yes
Mozilla Firefox: Yes
Opera: Yes
Safari: Yes

For the latest info, check out the MDN Web Docs compatibility table.

To get the most out of CSS text decoration, you might also find these properties helpful:

text-decoration: A shorthand for setting underline, overline, and line-through styles.
text-decoration-line: Sets the type of text decoration line.
text-decoration-color: Sets the color of the text decoration line.
text-decoration-style: Defines the style of the text decoration line (e.g., solid, double, dotted, dashed, wavy).

These properties give you more control over text decorations, helping you create visually appealing and readable web content.

By understanding and using the text-underline-position property effectively, you can enhance the visual appeal and readability of your text in various web design scenarios.