---
title: Pseudo-classes
slug: Web/CSS/Pseudo-classes
tags:
  - CSS
  - Panoramica
  - Pseudo-class
  - Riferimento
  - Selettori
translation_of: Web/CSS/Pseudo-classes
---
<div>{{CSSRef}}</div>

<p class="summary"><span class="seoSummary">Una <strong><dfn>pseudo-classe</dfn></strong> <a href="/it/docs/Web/CSS">CSS</a> è una parola chiave aggiunta ad un selettore la quale specifica lo stato speciale degli elementi selezionati.</span> Ad esempio, {{CSSxRef(":hover")}} può essere usato per cambiare il colore di un pulsate quando il puntatore dell'utente vi passa sopra.</p>

<pre class="brush: css no-line-numbers">/* Qualsiasi button sopra al quale passa il cursore dell'utente*/
button:hover {
  color: blue;
}</pre>

<p>La pseudo-classi permettono di applicare uno stile ad un elemento non solo in relazione al contenuto dell'alberatura del documento, ma anche in relazione a fattori esterni come la storia della navigazione ({{CSSxRef(":visited")}}, per esempio), lo stato del suo contenuto (come {{CSSxRef(":checked")}} su determinati elementi di form), oppure la posizione del mouse (come {{CSSxRef(":hover")}}), il quale permette di sapere se il mouse si trova su un elemento o no.</p>

<div class="blockIndicator note">
<p><strong>Nota:</strong> Al contrario delle pseudo-classi, gli <a href="/en-US/docs/Web/CSS/Pseudo-elements">pseudo-elementi</a> possono essere usati per dare stile a <em>parti specifiche</em> di un elemento.</p>
</div>

<h2 id="Sintassi">Sintassi</h2>

<pre class="syntaxbox">selector:pseudo-class {
  property: value;
}
</pre>

<p>Come per una classe regolare, è possibile concatenare insieme quante più pseudo-classi volute in un selettore.</p>

<h2 id="Indice_delle_pseudo-classi_standard">Indice delle pseudo-classi standard</h2>

<div class="index" id="index">
<ul>
 <li>{{CSSxRef(":active")}}</li>
 <li>{{CSSxRef(":any-link")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":blank")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":checked")}}</li>
 <li>{{CSSxRef(":current")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":default")}}</li>
 <li>{{CSSxRef(":defined")}}</li>
 <li>{{CSSxRef(":dir", ":dir()")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":disabled")}}</li>
 <li>{{CSSxRef(":drop")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":empty")}}</li>
 <li>{{CSSxRef(":enabled")}}</li>
 <li>{{CSSxRef(":first")}}</li>
 <li>{{CSSxRef(":first-child")}}</li>
 <li>{{CSSxRef(":first-of-type")}}</li>
 <li>{{CSSxRef(":fullscreen")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":future")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":focus")}}</li>
 <li>{{CSSxRef(":focus-visible")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":focus-within")}}</li>
 <li>{{CSSxRef(":has", ":has()")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":host")}}</li>
 <li>{{CSSxRef(":host()")}}</li>
 <li>{{CSSxRef(":host-context()")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":hover")}}</li>
 <li>{{CSSxRef(":indeterminate")}}</li>
 <li>{{CSSxRef(":in-range")}}</li>
 <li>{{CSSxRef(":invalid")}}</li>
 <li>{{CSSxRef(":is", ":is()")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":lang", ":lang()")}}</li>
 <li>{{CSSxRef(":last-child")}}</li>
 <li>{{CSSxRef(":last-of-type")}}</li>
 <li>{{CSSxRef(":left")}}</li>
 <li>{{CSSxRef(":link")}}</li>
 <li>{{CSSxRef(":local-link")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":not", ":not()")}}</li>
 <li>{{CSSxRef(":nth-child", ":nth-child()")}}</li>
 <li>{{CSSxRef(":nth-col", ":nth-col()")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":nth-last-child", ":nth-last-child()")}}</li>
 <li>{{CSSxRef(":nth-last-col", ":nth-last-col()")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":nth-last-of-type", ":nth-last-of-type()")}}</li>
 <li>{{CSSxRef(":nth-of-type", ":nth-of-type()")}}</li>
 <li>{{CSSxRef(":only-child")}}</li>
 <li>{{CSSxRef(":only-of-type")}}</li>
 <li>{{CSSxRef(":optional")}}</li>
 <li>{{CSSxRef(":out-of-range")}}</li>
 <li>{{CSSxRef(":past")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":placeholder-shown")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":read-only")}}</li>
 <li>{{CSSxRef(":read-write")}}</li>
 <li>{{CSSxRef(":required")}}</li>
 <li>{{CSSxRef(":right")}}</li>
 <li>{{CSSxRef(":root")}}</li>
 <li>{{CSSxRef(":scope")}}</li>
 <li>{{CSSxRef(":state", ":state()")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":target")}}</li>
 <li>{{CSSxRef(":target-within")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":user-invalid")}} {{Experimental_Inline}}</li>
 <li>{{CSSxRef(":valid")}}</li>
 <li>{{CSSxRef(":visited")}}</li>
 <li>{{CSSxRef(":where", ":where()")}} {{Experimental_Inline}}</li>
</ul>
</div>

<h2 id="Specifiche">Specifiche</h2>

<table class="standard-table">
 <thead>
  <tr>
   <th scope="col">Specifica</th>
   <th scope="col">Status</th>
   <th scope="col">Commento</th>
  </tr>
 </thead>
 <tbody>
  <tr>
   <td>{{SpecName("Fullscreen")}}</td>
   <td>{{Spec2("Fullscreen")}}</td>
   <td>Definito <code>:fullscreen</code>.</td>
  </tr>
  <tr>
   <td>{{SpecName("HTML WHATWG", "#pseudo-classes")}}</td>
   <td>{{Spec2("HTML WHATWG")}}</td>
   <td>Definisce quando particolari selettori corrisponde ad elementi HTML.</td>
  </tr>
  <tr>
   <td>{{SpecName("CSS4 Selectors")}}</td>
   <td>{{Spec2("CSS4 Selectors")}}</td>
   <td>Definiti <code style="white-space: nowrap;">:any-link</code>, <code>:blank</code>, <code style="white-space: nowrap;">:local-link</code>, <code>:scope</code>, <code>:drop</code>, <code>:current</code>, <code>:past</code>, <code>:future</code>, <code style="white-space: nowrap;">:placeholder-shown</code>, <code style="white-space: nowrap;">:user-invalid</code>, <code style="white-space: nowrap;">:nth-col()</code>, <code style="white-space: nowrap;">:nth-last-col()</code>, <code>:is()</code> e <code>:where()</code>.<br>
    Cambiato il comportamento di <code>:empty</code> {{CSSxRef(":-moz-only-whitespace")}} {{Non-standard_Inline}}.<br>
    Nessun cambiamento significativo per le altre pseudo-classi definite nel {{SpecName("CSS3 Selectors")}} e {{SpecName("HTML5 W3C")}} (sebbene il significato semantico non sia stato preso in considerazione).</td>
  </tr>
  <tr>
   <td>{{SpecName("HTML5 W3C")}}</td>
   <td>{{Spec2("HTML5 W3C")}}</td>
   <td>Copia della sezione pertinente dalla specifica canonica HTML (WHATWG).</td>
  </tr>
  <tr>
   <td>{{SpecName("CSS3 Basic UI")}}</td>
   <td>{{Spec2("CSS3 Basic UI")}}</td>
   <td>Definiti <code>:default</code>, <code>:valid</code>, <code>:invalid</code>, <code>:in-range</code>, <code>:out-of-range</code>, <code>:required</code>, <code>:optional</code>, <code>:read-only</code> and <code>:read-write</code>, ma senza l'associazione di significato semantico.</td>
  </tr>
  <tr>
   <td>{{SpecName("CSS3 Selectors")}}</td>
   <td>{{Spec2("CSS3 Selectors")}}</td>
   <td>Definiti <code>:target</code>, <code>:root</code>, <code>:nth-child()</code>, <code>:nth-last-of-child()</code>, <code>:nth-of-type()</code>, <code>:nth-last-of-type()</code>, <code>:last-child</code>, <code>:first-of-type</code>, <code>:last-of-type</code>, <code>:only-child</code>, <code>:only-of-type</code>, <code>:empty</code> e <code>:not()</code>.<br>
    Definita la sintassi di <code>:enabled</code>, <code>:disabled</code>, <code>:checked</code>, e <code>:indeterminate</code>, ma senza l'associazione di significato semantico.<br>
    Nessun cambiamento significativo per le pseudo-classi definite nel {{SpecName('CSS2.1')}}.</td>
  </tr>
  <tr>
   <td>{{SpecName("CSS2.1")}}</td>
   <td>{{Spec2("CSS2.1")}}</td>
   <td>Definiti <code>:lang()</code>, <code>:first-child</code>, <code>:hover</code>, e <code>:focus</code>.<br>
    Nessun cambiamento significativo per le pseudo-classi definite nel {{SpecName('CSS1')}}.</td>
  </tr>
  <tr>
   <td>{{SpecName("CSS1")}}</td>
   <td>{{Spec2("CSS1")}}</td>
   <td>Definiti <code>:link</code>, <code>:visited</code> e <code>:active</code>, ma senza l'associazione di significato semantico.</td>
  </tr>
 </tbody>
</table>

<h2 id="Vedi_anche">Vedi anche</h2>

<ul>
 <li><a href="/en-US/docs/Web/CSS/Pseudo-elements">Pseudo-elements</a></li>
</ul>