coliff/popover-css-inspector

Displays CSS attributes of elements in a Bootstrap popover. Ideal for design systems and style guides

v1.0.0-beta21 2026-04-14 01:47 UTC

MIT

• Christian Oliff

• css
• bootstrap
• style
• inspector

README

Popover CSS Inspector

Displays CSS attributes of elements in a Bootstrap popover. Ideal for design systems and style guides.

• Easy to use - just add data-bs-custom-class="popover-css-inspector" to the element (requires Bootstrap 5 JavaScript)
• Customizable with your own CSS and Bootstrap's Popover options
• Popover remains static on the document and does not reposition on scroll
• Supports Bootstrap 5 dark mode
• Option to hide CSS elements - e.g. just add data-css-inspector-hide="font-size" to prevent font-size properties from displaying
• Some CSS properties are hidden by default but can be enabled - e.g. just add data-css-inspector-show="border" to show border properties
• Reloads CSS attributes if the theme is changed via the data-bs-theme attribute - perfect for checking color value changes between light and dark mode
• Supports optional title with data-bs-title attribute.
• Only 3 KB minified and gzipped!

Quick start

Several quick start options are available:

• Download the latest release
• Clone the repo git clone https://github.com/coliff/popover-css-inspector.git
• Install with npm npm install popover-css-inspector
• Install with yarn yarn add popover-css-inspector
• Install with Composer composer require coliff/popover-css-inspector

Usage

1. Add the data-bs-custom-class="popover-css-inspector" to the element you'd like to show the popover on. For example, a button.

<button
  type="button"
  class="btn btn-primary"
  data-bs-toggle="popover"
  data-bs-custom-class="popover-css-inspector">
  Button
</button>

1. Load the script (either async or defer is recommended):

<script src="/js/popover-css-inspector.min.js" defer></script>

1. Some CSS properties are opt-in only. For example, to show border properties, add data-css-inspector-show="border" to the element.

2. All CSS properties can be hidden. For example, to hide font-size properties, add data-css-inspector-hide="font-size" to the element.

3. Optional. Consider adding the pe-none class to the element to prevent the popover from being triggered by the user.

How it works

The script will look for any element with the data-bs-custom-class="css-inspector" attribute and add a click event listener to it. When clicked, it will get the element's CSS attributes and display them in a Bootstrap popover.

Demo

Demo page

List of CSS properties

These CSS properties are displayed by default unless their value is null or empty. You can opt out of these rows with data-css-inspector-hide.

Property	Opt-out attribute
animation-duration	data-css-inspector-hide="animation-duration"
animation-name	data-css-inspector-hide="animation-name"
background-color	data-css-inspector-hide="bg-color"
border-radius	data-css-inspector-hide="b-radius"
color	data-css-inspector-hide="color"
font-size	data-css-inspector-hide="font-size"
font-style	data-css-inspector-hide="font-style"
font-weight	data-css-inspector-hide="font-weight"
height	data-css-inspector-hide="height"
margin	data-css-inspector-hide="margin"
max-height	data-css-inspector-hide="max-height"
max-width	data-css-inspector-hide="max-width"
opacity	data-css-inspector-hide="opacity"
padding	data-css-inspector-hide="padding"
text-align	data-css-inspector-hide="text-align"
text-transform	data-css-inspector-hide="text-transform"
width	data-css-inspector-hide="width"

Note: Most attributes are hidden if the value is none or null.

List of opt-in CSS properties

These CSS properties are hidden by default and are only shown when included in data-css-inspector-show.

Property	Opt-in attribute
accent-color	data-css-inspector-show="accent-color"
align-content	data-css-inspector-show="align-content"
align-items	data-css-inspector-show="align-items"
align-self	data-css-inspector-show="align-self"
animation	data-css-inspector-show="animation"
animation-delay	data-css-inspector-show="animation-delay"
animation-direction	data-css-inspector-show="animation-direction"
animation-fill-mode	data-css-inspector-show="animation-fill-mode"
animation-iteration-count	data-css-inspector-show="animation-iteration-count"
animation-play-state	data-css-inspector-show="animation-play-state"
animation-timing-function	data-css-inspector-show="animation-timing-function"
appearance	data-css-inspector-show="appearance"
aspect-ratio	data-css-inspector-show="aspect-ratio"
backdrop-filter	data-css-inspector-show="backdrop-filter"
background-blend-mode	data-css-inspector-show="background-blend-mode"
background-image	data-css-inspector-show="bg-image"
background-position	data-css-inspector-show="bg-position"
background-repeat	data-css-inspector-show="bg-repeat"
background-size	data-css-inspector-show="bg-size"
border	data-css-inspector-show="border"
border-bottom-color	data-css-inspector-show="b-bottom-color"
border-bottom-width	data-css-inspector-show="b-bottom-width"
border-color	data-css-inspector-show="b-color"
border-left-width	data-css-inspector-show="b-left-width"
border-style	data-css-inspector-show="b-style"
border-width	data-css-inspector-show="b-width"
box-shadow	data-css-inspector-show="box-shadow"
box-sizing	data-css-inspector-show="box-sizing"
clip-path	data-css-inspector-show="clip-path"
column-gap	data-css-inspector-show="column-gap"
color-scheme	data-css-inspector-show="color-scheme"
cursor	data-css-inspector-show="cursor"
display	data-css-inspector-show="display"
filter	data-css-inspector-show="filter"
float	data-css-inspector-show="float"
flex-direction	data-css-inspector-show="flex-direction"
flex-wrap	data-css-inspector-show="flex-wrap"
font-family	data-css-inspector-show="font-family"
font-variant	data-css-inspector-show="font-variant"
gap	data-css-inspector-show="gap"
grid-auto-flow	data-css-inspector-show="grid-auto-flow"
grid-column	data-css-inspector-show="grid-column"
grid-row	data-css-inspector-show="grid-row"
grid-template-columns	data-css-inspector-show="grid-template-columns"
grid-template-rows	data-css-inspector-show="grid-template-rows"
hyphens	data-css-inspector-show="hyphens"
isolation	data-css-inspector-show="isolation"
justify-items	data-css-inspector-show="justify-items"
justify-self	data-css-inspector-show="justify-self"
letter-spacing	data-css-inspector-show="letter-spacing"
line-break	data-css-inspector-show="line-break"
line-height	data-css-inspector-show="line-height"
list-style	data-css-inspector-show="list-style"
margin-bottom	data-css-inspector-show="margin-bottom"
margin-left	data-css-inspector-show="margin-left"
margin-right	data-css-inspector-show="margin-right"
margin-top	data-css-inspector-show="margin-top"
mix-blend-mode	data-css-inspector-show="mix-blend-mode"
min-height	data-css-inspector-show="min-height"
min-width	data-css-inspector-show="min-width"
object-fit	data-css-inspector-show="object-fit"
object-position	data-css-inspector-show="object-position"
overflow	data-css-inspector-show="overflow"
overflow-wrap	data-css-inspector-show="overflow-wrap"
outline	data-css-inspector-show="outline"
outline-offset	data-css-inspector-show="outline-offset"
place-content	data-css-inspector-show="place-content"
place-items	data-css-inspector-show="place-items"
pointer-events	data-css-inspector-show="pointer-events"
position	data-css-inspector-show="position"
row-gap	data-css-inspector-show="row-gap"
text-decoration	data-css-inspector-show="text-decoration"
text-decoration-thickness	data-css-inspector-show="text-decoration-thickness"
text-indent	data-css-inspector-show="text-indent"
text-overflow	data-css-inspector-show="text-overflow"
text-shadow	data-css-inspector-show="text-shadow"
text-underline-offset	data-css-inspector-show="text-underline-offset"
text-wrap	data-css-inspector-show="text-wrap"
transform	data-css-inspector-show="transform"
transform-origin	data-css-inspector-show="transform-origin"
transition	data-css-inspector-show="transition"
transition-delay	data-css-inspector-show="transition-delay"
transition-duration	data-css-inspector-show="transition-duration"
transition-property	data-css-inspector-show="transition-property"
transition-timing-function	data-css-inspector-show="transition-timing-function"
user-select	data-css-inspector-show="user-select"
vertical-align	data-css-inspector-show="vertical-align"
white-space	data-css-inspector-show="white-space"
will-change	data-css-inspector-show="will-change"
writing-mode	data-css-inspector-show="writing-mode"
word-break	data-css-inspector-show="word-break"
word-spacing	data-css-inspector-show="word-spacing"
word-wrap	data-css-inspector-show="word-wrap"
z-index	data-css-inspector-show="z-index"

Browser support

Works well with all the browsers supported by Bootstrap.

Credits

Created by Christian Oliff with help from GitHub Copilot.