Bootstrap 4 Utilità
Bootstrap 4 Utilità
Bootstrap 4 ha molte classi di utilità/helper per definire rapidamente gli elementi senza utilizzare alcun codice CSS.
frontiere
Usa le border
classi per aggiungere o rimuovere bordi da un elemento:
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<span class="border"></span>
<span class="border border-0"></span>
<span class="border border-top-0"></span>
<span class="border border-right-0"></span>
<span
class="border border-bottom-0"></span>
<span class="border border-left-0"></span>
Colore del bordo
Aggiungi un colore al bordo con una qualsiasi delle classi contestuali di colore del bordo:
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<span class="border border-primary"></span>
<span class="border
border-secondary"></span>
<span class="border border-success"></span>
<span class="border border-danger"></span>
<span class="border
border-warning"></span>
<span class="border border-info"></span>
<span class="border border-light"></span>
<span class="border
border-dark"></span>
<span class="border border-white"></span>
Raggio di confine
Aggiungi angoli arrotondati a un elemento con le rounded
classi:
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<span class="rounded-sm"></span>
<span class="rounded"></span>
<span class="rounded-lg"></span>
<span class="rounded-top"></span>
<span class="rounded-right"></span>
<span
class="rounded-bottom"></span>
<span class="rounded-left"></span>
<span class="rounded-circle"></span>
<span
class="rounded-0"></span>
Float e Clearfix
Porta un elemento a destra con la .float-right
classe o a sinistra con .float-left
, e cancella i float con la .clearfix
classe:
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<div class="clearfix">
<span class="float-left">Float left</span>
<span
class="float-right">Float right</span>
</div>
Galleggianti reattivi
Sposta un elemento a sinistra o a destra a seconda della larghezza dello schermo, con le classi float reattive ( .float-*-left|right
- dove * è sm
(>=576px), md
(>=768px), lg
(>=992px) o xl
(>=1200px)):
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<div class="float-sm-right">Float right on small screens or wider</div><br>
<div class="float-md-right">Float right on medium screens or wider</div><br>
<div class="float-lg-right">Float right on large screens or wider</div><br>
<div class="float-xl-right">Float right on extra large screens or
wider</div><br>
<div class="float-none">Float none</div>
Allinea al centro
Centrare un elemento con la .mx-auto
classe (aggiunge margine sinistro e margine destro: auto):
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<div class="mx-auto
bg-warning" style="width:150px">Centered</div>
Larghezza
Imposta la larghezza di un elemento con le classi w-* ( .w-25
, .w-50
, .w-75
, .w-100
, .mw-100
):
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<div class="w-25 bg-warning">Width 25%</div>
<div class="w-50 bg-warning">Width
50%</div>
<div class="w-75 bg-warning">Width 75%</div>
<div
class="w-100 bg-warning">Width 100%</div>
<div class="mw-100 bg-warning">Max Width 100%</div>
Altezza
Imposta l'altezza di un elemento con le classi h-* ( .h-25
, .h-50
, .h-75
, .h-100
, .mh-100
):
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<div style="height:200px;background-color:#ddd">
<div class="h-25 bg-warning">Height 25%</div>
<div class="h-50 bg-warning">Height
50%</div>
<div class="h-75 bg-warning">Height 75%</div>
<div
class="h-100 bg-warning">Height 100%</div>
<div class="mh-100 bg-warning"
style="height:500px">Max Height 100%</div>
</div>
Spaziatura
Bootstrap 4 ha un'ampia gamma di classi di utilità di riempimento e margini reattivi. Funzionano per tutti i punti di interruzione: xs
(<=576px), sm
(>=576px), md
(>=768px), lg
(>=992px) o xl
(>=1200px)):
Le classi vengono utilizzate nel formato: {property}{sides}-{size}
for xs
e {property}{sides}-{breakpoint}-{size}
for sm
, md
, lg
e xl
.
Dove la proprietà è una di:
m
- impostamargin
p
- impostapadding
Dove i lati è uno di:
t
- impostamargin-top
opadding-top
b
- impostamargin-bottom
opadding-bottom
l
- impostamargin-left
opadding-left
r
- impostamargin-right
opadding-right
x
- imposta entrambipadding-left
epadding-right
omargin-left
emargin-right
y
- imposta entrambipadding-top
epadding-bottom
omargin-top
emargin-bottom
- vuoto - imposta a
margin
opadding
su tutti e 4 i lati dell'elemento
Dove la dimensione è una di:
0
- impostamargin
opadding
a0
1
- impostamargin
opadding
su.25rem
(4px se la dimensione del carattere è 16px)2
- impostamargin
opadding
su.5rem
(8px se la dimensione del carattere è 16px)3
- impostamargin
opadding
su1rem
(16px se la dimensione del carattere è 16px)4
- impostamargin
opadding
su1.5rem
(24px se la dimensione del carattere è 16px)5
- impostamargin
opadding
su3rem
(48px se la dimensione del carattere è 16px)auto
- impostamargin
su automatico
Nota: i margini possono anche essere negativi, aggiungendo una "n" davanti alla dimensione :
n1
- impostamargin
su-.25rem
(-4px se la dimensione del carattere è 16px)n2
- impostamargin
su-.5rem
(-8px se la dimensione del carattere è 16px)n3
- impostamargin
su-1rem
(-16px se la dimensione del carattere è 16px)n4
- impostamargin
su-1.5rem
(-24px se la dimensione del carattere è 16px)n5
- impostamargin
su-3rem
(-48px se la dimensione del carattere è 16px)
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<div class="pt-4 bg-warning">I only have a top padding (1.5rem =
24px)</div>
<div class="p-5 bg-success">I have a padding on all sides
(3rem = 48px)</div>
<div class="m-5 pb-5 bg-info">I have a margin on
all sides (3rem = 48px) and a bottom padding (3rem = 48px)</div>
Altri esempi di spaziatura
.m-# / m-*-# |
margine su tutti i lati | |
.mt-# / mt-*-# |
margine superiore | |
.mb-# / mb-*-# |
margine inferiore | |
.ml-# / ml-*-# |
margine sinistro | |
.mr-# / mr-*-# |
margine a destra | |
.mx-# / mx-*-# |
margine sinistro e destro | |
.my-# / my-*-# |
margine superiore e inferiore | |
.p-# / p-*-# |
imbottitura su tutti i lati | |
.pt-# / pt-*-# |
parte superiore imbottita | |
.pb-# / pb-*-# |
fondo imbottito | |
.pl-# / pl-*-# |
imbottitura a sinistra | |
.pr-# / pr-*-# |
imbottitura a destra | |
.py-# / py-*-# |
imbottitura superiore e inferiore | |
.px-# / px-*-# |
riempimento a sinistra e a destra |
Ombre
Usa le shadow-
classi per aggiungere ombre a un elemento:
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<div class="shadow-none p-4 mb-4 bg-light">No shadow</div>
<div
class="shadow-sm p-4 mb-4 bg-white">Small
shadow</div>
<div class="shadow p-4 mb-4 bg-white">Default
shadow</div>
<div class="shadow-lg p-4 mb-4 bg-white">Large
shadow</div>
Allineamento verticale
Usa le align-
classi per modificare l'allineamento degli elementi (funziona solo su elementi inline, inline-block, inline-table e table cell):
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<span class="align-baseline">baseline</span>
<span
class="align-top">top</span>
<span class="align-middle">middle</span>
<span class="align-bottom">bottom</span>
<span
class="align-text-top">text-top</span>
<span
class="align-text-bottom">text-bottom</span>
Incorporamenti reattivi
Crea incorporamenti di video reattivi o presentazioni in base alla larghezza del genitore.
Aggiungi .embed-responsive-item
a qualsiasi elemento da incorporare (come <iframe> o <video>) in un elemento genitore con .embed-responsive
e proporzioni a tua scelta:
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<!-- 21:9 aspect ratio -->
<div class="embed-responsive
embed-responsive-21by9">
<iframe class="embed-responsive-item"
src="..."></iframe>
</div>
<!-- 16:9 aspect ratio -->
<div class="embed-responsive
embed-responsive-16by9">
<iframe class="embed-responsive-item"
src="..."></iframe>
</div>
<!-- 4:3 aspect ratio -->
<div class="embed-responsive
embed-responsive-4by3">
<iframe class="embed-responsive-item"
src="..."></iframe>
</div>
<!-- 1:1 aspect ratio -->
<div class="embed-responsive
embed-responsive-1by1">
<iframe class="embed-responsive-item"
src="..."></iframe>
</div>
Visibilità
Utilizzare le classi .visible
o per controllare la visibilità degli elementi. Nota: queste classi non modificano il valore di visualizzazione CSS. Aggiungono solo o :.invisible
visibility:visible
visibility:hidden
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<div class="visible">I am visible</div>
<div class="invisible">I am
invisible</div>
Posizione
Usa la .fixed-top
classe per rendere fisso/rimanere qualsiasi elemento nella parte superiore della pagina:
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<nav class="navbar navbar-expand-sm bg-dark navbar-dark fixed-top">
...
</nav>
Use the .fixed-bottom
class to make any element fixed/stay at
the bottom of the page:
Example
<nav class="navbar navbar-expand-sm bg-dark navbar-dark fixed-bottom">
...
</nav>
Use the .sticky-top
class to make any element fixed/stay at
the top of the page when you scroll past it. Note:
This class does not work in IE11 and earlier (will treat it as position:relative
).
Example
<nav class="navbar navbar-expand-sm bg-dark navbar-dark sticky-top">
...
</nav>
Close icon
Use the .close
class to style a close icon. This is often used for alerts and modals. Note that we use the ×
symbol to create the actual icon (a better looking
"x"). Also note that it floats right by default:
Example
Example
<button type="button" class="close">×</button>
Screenreaders
Use the .sr-only
class to hide an element on all devices, except screen readers:
Example
<span class="sr-only">I will be hidden on all screens except for screen
readers.</span>
Colors
As described in the Colors chapter, here is a list of all text and background color classes:
The classes for text colors are: .text-muted
,
.text-primary
, .text-success
, .text-info
,
.text-warning
, .text-danger
, .text-secondary
, .text-white
,
.text-dark
, .text-body
(default body color/often black) and .text-light
:
Example
This text is muted.
This text is important.
This text indicates success.
This text represents some information.
This text represents a warning.
This text represents danger.
Secondary text.
Dark grey text.
Body text.
Light grey text.
Contextual text classes can also be used on links, which will add a darker hover color:
Example
You can also add 50% opacity for black or white text with the .text-black-50
or .text-white-50
classes:
Example
Black text with 50% opacity on white background
White text with 50% opacity on black background
Background Colors
The classes for background colors are: .bg-primary
,
.bg-success
, .bg-info
, .bg-warning
, .bg-danger
, .bg-secondary
, .bg-dark
and .bg-light
.
Note that background colors do not set the text color, so in some cases you'll want to use them together with a .text-*
class.
Example
This text is important.
This text indicates success.
This text represents some information.
This text represents a warning.
This text represents danger.
Secondary background color.
Dark grey background color.
Light grey background color.
Typography/Text Classes
As described in the Typography chapter, here is a list of all typography/text classes:
Class | Description | Example |
---|---|---|
.display-* |
Display headings are used to stand out more than normal headings (larger font-size and lighter font-weight), and there are four classes to choose from: .display-1 , .display-2 , .display-3 , .display-4 |
|
.font-weight-bold |
Bold text | |
.font-weight-bolder |
Bolder bold text | |
.font-weight-normal |
Normal text | |
.font-weight-light |
Light weight text | |
.font-weight-lighter |
Lighter weight text | |
.font-italic |
Italic text | |
.lead |
Makes a paragraph stand out | |
.small |
Indicates smaller text (set to 85% of the size of the parent) | |
.text-break |
Prevents long text from breaking layout | |
.text-center |
Indicates center-aligned text | |
.text-decoration-none |
Removes the underline from a link | |
.text-left |
Indicates left-aligned text | |
.text-justify |
Indicates justified text | |
.text-monospace |
Monospaced text | |
.text-nowrap |
Indicates no wrap text | |
.text-lowercase |
Indicates lowercased text | |
.text-reset |
Resets the color of a text or a link (inherits the color from its parent) | |
.text-right |
Indicates right-aligned text | |
.text-uppercase |
Indicates uppercased text | |
.text-capitalize |
Indicates capitalized text | |
.initialism |
Displays the text inside an <abbr> element in a slightly smaller font size |
|
.list-unstyled |
Removes the default list-style and left margin on list items (works on both <ul> and <ol> ). This class only applies to immediate children list items (to remove the default list-style from any nested lists, apply this class to any nested lists as well) |
|
.list-inline |
Places all list items on a single line (used together with
.list-inline-item on each <li> elements) |
|
.pre-scrollable |
Makes a <pre> element scrollable |
Block Elements
To make an element into a block element, add the .d-block
class. Use any of the d-*-block
classes to control WHEN the element should be a block element on a specific screen width:
Example
Example
<span class="d-block bg-success">d-block</span>
<span class="d-sm-block
bg-success">d-sm-block</span>
<span class="d-md-block bg-success">d-md-block</span>
<span class="d-lg-block bg-success">d-lg-block</span>
<span
class="d-xl-block bg-success">d-xl-block</span>
Other Display Classes
Other display classes are also available:
Class | Description | Example |
---|---|---|
.d-none |
Hides an element | |
.d-*-none |
Hides an element on a specific screen size | |
.d-inline |
Makes an element inline | |
.d-*-inline |
Makes an element inline on a specific screen size | |
.d-inline-block |
Makes an element inline block | |
.d-*-inline-block |
Makes an element inline block on a specific screen size | |
.d-table |
Makes an element display as a table | |
.d-*-table |
Makes an element display as a table on a specific screen size | |
.d-table-cell |
Makes an element display as a table cell | |
.d-*-table-cell |
Makes an element display as a table cell on a specific screen size | |
.d-table-row |
Makes an element display as a table row | |
.d-*-table-row |
Makes an element display as a table row on a specific screen size | |
.d-flex |
Creates a flexbox container and transforms direct children into flex items | |
.d-*-flex |
Creates a flexbox container on a specific screen size | |
.d-inline-flex |
Creates an inline flexbox container | |
.d-*-inline-flex |
Creates an inline flexbox container on a specific screen size |
Flex
Use .flex-*
classes to control the layout with flexbox.
Read more about Bootstrap 4 Flex, in our next chapter.
Example
Horizontal:
Vertical: