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---
title: Web Console Helpers
slug: Tools/Web_Console/Helpers
translation_of: Tools/Web_Console/Helpers
---
<h2 id="I_comandi"><strong>I comandi</strong></h2>
<p>la riga di comando JavaScript fornito dalla console web offre alcune funzioni di supporto built-in che rendono più semplici determinate attivita</p>
<dl>
<dt id="$"><code>$()</code></dt>
<dd><span id="result_box" lang="it"><span>Sembra</span> <span>una stringa</span> <span>selettore CSS</span><span>, restituendo il</span> <span>primo elemento</span> <span>che corrisponde</span><span>.</span> <span>Equivalente a</span> <span>{</span><span>{</span><span>domxref</span> <span>(</span><span>"</span><span>document.querySelector</span> <span>(</span><span>)")</span><span>}</span><span>}</span> <span>o</span> <span>chiama la funzione</span> <span>$</span> <span>nella pagina</span><span>,</span> <span>se esiste</span></span></dd>
<dt id="$$"><code>$$()</code></dt>
<dd><span id="result_box" lang="it"><span>Sembra</span> <span>una stringa</span> <span>selettore CSS</span><span>,</span> <span>restituendo</span> <span>una serie di</span> <span>nodi DOM</span> <span>quella partita</span><span>.</span> <span>Questo è come</span> <span>per {</span><span>{</span><span>domxref</span> <span>(</span><span>"</span><span>document.querySelectorAll</span> <span>(</span><span>)</span><span>"</span><span>)</span><span>}</span><span>}</span><span>,</span> <span>ma</span> <span>restituisce un array</span> <span>invece di un</span> <span>{</span><span>{</span><span>domxref</span> <span>(</span><span>"</span><span>NodeList</span><span>"</span><span>)</span><span>}</span><span>}</span><span>.</span></span></dd>
<dt id="$0"><code>$0</code></dt>
<dd><span class="short_text" id="result_box" lang="it"><span>L'elemento</span> <span>attualmente</span> <span>ispezionato</span> <span>nella pagina</span><span>.</span></span></dd>
<dt id="$_"><code>$_</code></dt>
<dd><span id="result_box" lang="it"><span>Memorizza il risultato</span> <span>dell'ultima espressione</span> <span>eseguito</span> <span>nella linea di comando</span> <span>console</span><span>.</span> <span>Ad</span> <span>esempio,</span> <span>se si digita</span> <span>"</span><span>2</span> <span>+</span> <span>2</span> <span><Enter</span><span>></span><span>"</span><span>,</span> <span>quindi</span> <span>"$</span> <span>_</span> <span><invio</span><span>></span><span>"</span><span>, la console</span> <span>stampare</span> <span>4</span><span>.</span></span></dd>
<dt id="$x"><code>$x()</code></dt>
<dd><span id="result_box" lang="it"><span>Valuta un'espressione</span> <span>XPath</span> <span>e restituisce</span> <span>un array di nodi</span> <span>corrispondenti</span><span>.</span></span></dd>
<dt id="keys"><code>keys()</code></dt>
<dd><span id="result_box" lang="it"><span>Dato un</span> <span>oggetto</span><span>,</span> <span>restituisce</span> <span>un elenco</span> <span>dei tasti</span> <span>(</span><span>o nomi</span> <span>di proprietà)</span> <span>su tale oggetto</span><span>.</span> <span>Questa</span> <span>è una scorciatoia per</span> <span>Object.keys</span><span>.</span></span></dd>
<dt id="values"><code>values()</code></dt>
<dd><span id="result_box" lang="it"><span>Dato un</span> <span>oggetto</span><span>,</span> <span>restituisce una lista</span> <span>dei</span> <span>valori</span> <span>di</span> <span>tale oggetto</span><span>;</span> <span>serve come</span> <span>un compagno di</span> <span>chiavi</span> <span>(</span><span>)</span><span>.</span></span></dd>
<dt id="clear"><code>clear()</code></dt>
<dd><span class="short_text" id="result_box" lang="it"><span>Cancella l'</span><span>area di uscita</span> <span>della console</span><span>.</span></span></dd>
<dt id="inspect"><code>inspect()</code></dt>
<dd><span id="result_box" lang="it"><span>Dato un</span> <span>oggetto</span><span>,</span> <span>si apre</span> <span>la finestra di ispezione</span> <span>oggetto per</span> <span>quell'oggetto</span><span>.</span></span></dd>
<dt id="pprint"><code>pprint()</code></dt>
<dd><span id="result_box" lang="it"><span>Formatta il</span> <span>valore specificato</span> <span>in modo</span> <span>leggibile</span><span>;</span> <span>questo è utile</span> <span>per lo scarico</span> <span>del contenuto di</span> <span>oggetti</span> <span>e array</span><span>.</span></span></dd>
<dt id="help"><code>help()</code></dt>
<dd><span id="result_box" lang="it"><span>Visualizza la guida</span> <span>del testo</span><span>.</span> <span>In realtà</span><span>,</span> <span>in un delizioso</span> <span>esempio di</span> <span>ricorsione</span><span>,</span> <span>che</span> <span>vi porterà a</span> <span>questa pagina.</span></span></dd>
<dt id="cd"><code>cd()</code></dt>
<dd>
<p><span id="result_box" lang="it"><span>Interruttore</span> <span>contesto di valutazione</span> <span>JavaScript per</span> <span>un</span> <span>iframe</span> <span>diversa all'interno della pagina</span><span>.</span> <span>Questo</span> <span>helper</span> <span>accetta più</span> <span>modi diversi</span> <span>di identificazione</span> <span>del telaio</span> <span>per passare</span><span>.</span> <span>È possibile fornire</span> <span>una delle seguenti</span><span>:</span></span></p>
<ul>
<li><span id="result_box" lang="it"><span>una stringa</span> <span>selettore che</span> <span>verrà</span> <span>passato al</span> <span>document.querySelector</span> <span>per individuare l'</span><span>elemento</span> <span>iframe</span></span></li>
<li><span class="short_text" id="result_box" lang="it"><span>l'elemento</span> <span>iframe</span> <span>stesso</span></span></li>
<li><span class="short_text" id="result_box" lang="it"><span>la</span> <span>finestra di contenuto</span> <span>all'interno del</span> <span>iframe</span></span></li>
</ul>
<p><span class="short_text" id="result_box" lang="it"><span>Vedere</span> <span>lavorare con</span> <span>iframe</span></span></p>
</dd>
<dt id="copy"><code>copy()</code></dt>
<dd><span id="result_box" lang="it"><span>Nuovo</span> <span>in Firefox</span> <span>38.</span> <span>Copia</span> <span>l'argomento</span> <span>negli appunti</span><span>.</span> <span>Se l'argomento</span> <span>è una stringa</span><span>,</span> <span>viene copiato</span> <span>così com'è</span><span>.</span> <span>Se l'argomento</span> <span>è un nodo</span> <span>DOM</span><span>,</span> <span>la sua</span> <span>outerHTML</span> <span>viene copiato</span><span>.</span> <span>In caso contrario</span><span>,</span> <span>JSON.stringify</span> <span>sarà chiamato</span> <span>sull'argomento</span><span>,</span> <span>e il risultato</span> <span>sarà</span> <span>copiata negli appunti</span><span>.</span></span></dd>
<dt id="clearHistory"><code>clearHistory()</code></dt>
<dd>.<span id="result_box" lang="it"><span>Nuovo</span> <span>in Firefox</span> <span>39.</span> <span>Proprio come una</span> <span>normale</span> <span>linea di comando</span><span>,</span> <span>la</span> <span>riga di comando</span> <span>della console</span> <span>ricorda</span> <span>i comandi</span> <span>che avete</span> <span>digitato</span><span>.</span> <span>Utilizzare questa funzione per</span> <span>cancellare la cronologia</span> <span>dei comandi</span> <span>della console</span><span>.</span></span></dd>
</dl>
<p><span id="result_box" lang="it"><span>Si prega di</span> <span>fare riferimento alla</span> <span>API</span> <span>Console</span> <span>per</span> <span>maggiori informazioni sulla connessione</span> <span>dal contenuto</span><span>.</span></span></p>
<h2 id="variabili"><strong>variabili</strong></h2>
<dl>
<dt id="tempN">temp<em>N</em></dt>
<dd><span id="result_box" lang="it"><span>L'opzione "</span><span>Use</span> <span>in</span> <span>Console"</span> <span>in Impostazioni</span> <span>genera una</span> <span>variabile per un</span> <span>nodo denominato</span> <span>temp0</span><span>,</span> <span>temp1</span><span>,</span> <span>temp2</span><span>,</span> <span>ecc</span> <span>riferimento al</span> <span>nodo.</span></span></dd>
</dl>
<h2 id="esempi">esempi</h2>
<h3 id="Guardando_il_contenuto_di_un_nodo_DOM"><span class="short_text" id="result_box" lang="it"><span>Guardando</span> <span>il contenuto di un</span> <span>nodo DOM</span></span></h3>
<p><span id="result_box" lang="it"><span>Diciamo che</span> <span>hai un</span> <span>nodo DOM</span> <span>con</span> <span>il "titolo</span><span>"</span> <span>ID</span><span>.</span> <span>In realtà,</span> <span>questa pagina</span> <span>che stai leggendo</span> <span>in questo momento</span> <span>ha uno,</span> <span>in modo da poter</span> <span>aprire</span> <span>la console Web</span> <span>e provare questo</span> <span>momento.</span></span></p>
<p><span id="result_box" lang="it"><span>Diamo uno</span> <span>sguardo ai</span> <span>contenuti</span> <span>di quel</span> <span>nodo utilizzando</span> <span>il</span> <span>$</span> <span>(</span><span>)</span> <span>e</span> <span>ispezionare</span> <span>(</span><span>)</span> <span>funzioni:</span></span></p>
<pre class="brush:js">inspect($("#title"))</pre>
<p><span id="result_box" lang="it"><span>Questo apre</span> <span>automaticamente</span> <span>l'ispettore</span> <span>oggetto</span><span>,</span> <span>che mostra</span> <span>il contenuto del</span> <span>nodo DOM</span> <span>che corrisponde al</span> <span>selettore CSS</span> <span>"</span><span>#title</span><span>"</span><span>,</span> <span>che è</span> <span>ovviamente</span> <span>l'elemento con</span> <span>ID</span> <span>"titolo"</span><span>.</span></span></p>
<h3 id="Dumping_il_contenuto_di_un_nodo_DOM"><span class="short_text" id="result_box" lang="it"><span>Dumping</span> <span>il contenuto di un</span> <span>nodo DOM</span></span></h3>
<p><span id="result_box" lang="it"><span>Questo è</span> <span>molto bello</span><span>, se</span> <span>vi capita di essere</span> <span>seduti al</span> <span>browser</span> <span>esporre</span> <span>qualche problema</span><span>,</span> <span>ma diciamo</span> <span>che stai</span> <span>debug</span> <span>remoto</span> <span>per un utente</span><span>,</span> <span>e hanno bisogno di</span> <span>uno sguardo</span> <span>il contenuto di un</span> <span>nodo.</span> <span>Si può avere</span> <span>l'utente</span> <span>aprire la console</span> <span>Web</span> <span>e</span> <span>scaricare il contenuto</span> <span>del nodo</span> <span>nel registro</span><span>,</span> <span>quindi copiare e incollare</span> <span>in</span> <span>una e-mail</span> <span>a voi</span><span>, utilizzando la funzione</span> <span>pprint</span> <span>(</span><span>)</span><span>:</span></span></p>
<pre class="brush:js">pprint($("#title"))
</pre>
<p><span id="result_box" lang="it"><span>Questo</span> <span>sputa</span> <span>fuori</span> <span>il contenuto</span> <span>del nodo</span> <span>in modo da poter</span> <span>dare un'occhiata</span><span>.</span> <span>Naturalmente</span><span>,</span> <span>questo può essere più</span> <span>utile</span> <span>con altri oggetti</span> <span>che un</span> <span>nodo DOM</span><span>,</span> <span>ma</span> <span>si ottiene l'idea</span><span>.</span></span></p>
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