Revision 784277 of for each...in

<div>{{jsSidebar("Statements")}}</div>

<div class="warning">
<p>The <code>for each...in</code> statement is deprecated as the part of ECMA-357 (<a href="/en-US/docs/Archive/Web/E4X" title="/en-US/docs/E4X">E4X</a>) standard. E4X support has been removed, but for each...in will not be disabled and removed because of backward compatibility considerations. Consider using <a href="/en-US/docs/Web/JavaScript/Reference/Statements/for...of" title="/en-US/docs/JavaScript/Reference/Statements/for...of">for...of</a> instead. (Please refer to {{ bug("791343")}}.)</p>
</div>

<p>The<code> <strong>for each...in</strong></code><strong> statement</strong> iterates a specified variable over all values of object's properties. For each distinct property, a specified statement is executed.</p>

<h2 id="Syntax">Syntax</h2>

<pre class="syntaxbox">
<code>for each (<em>variable</em> in <em>object</em>) {
  <em>statement</em>
}</code></pre>

<dl>
 <dt><code>variable</code></dt>
 <dd>Variable to iterate over property values, optionally declared with the <code>var</code> keyword. This variable is local to the function, not to the loop.</dd>
</dl>

<dl>
 <dt><code>object</code></dt>
 <dd>Object for which the properties are iterated.</dd>
</dl>

<dl>
 <dt><code>statement</code></dt>
 <dd>A statement to execute for each property. To execute multiple statements within the loop, use a <a href="/en-US/docs/Web/JavaScript/Reference/Statements/block" title="JavaScript/Reference/Statements/block">block</a> statement (<code>{ ... }</code>) to group those statements.</dd>
</dl>

<h2 id="Description">Description</h2>

<p>Some built-in properties are not iterated over. These include all built-in methods of objects, e.g. <code>String</code>'s <code>indexOf</code> method. However, all user-defined properties are iterated over.</p>

<h2 id="Examples">Examples</h2>

<h3 id="Using_for_each...in">Using <code>for each...in</code></h3>

<p><strong>Warning:</strong> Never use a loop like this on arrays. Only use it on objects. See <a href="/en-US/docs/Web/JavaScript/Reference/Statements/for...in"><code>for...in</code></a> for more details.</p>

<p>The following snippet iterates over an object's properties, calculating their sum:</p>

<pre class="brush:js">
var sum = 0;
var obj = {prop1: 5, prop2: 13, prop3: 8};

for each (var item in obj) {
  sum += item;
}

console.log(sum); // logs "26", which is 5+13+8</pre>

<h2>Specifications</h2>

<p>Not part of a current ECMA-262 specification. Implemented in JavaScript 1.6 and deprecated.</p>

<h2 id="Browser_compatibility">Browser compatibility</h2>

<p>{{CompatibilityTable}}</p>

<div id="compat-desktop">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Chrome</th>
   <th>Firefox (Gecko)</th>
   <th>Internet Explorer</th>
   <th>Opera</th>
   <th>Safari</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatGeckoDesktop("1.8")}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatNo}}</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android</th>
   <th>Chrome for Android</th>
   <th>Firefox Mobile (Gecko)</th>
   <th>IE Mobile</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatGeckoMobile("1.0")}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatNo}}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="See_also">See also</h2>

<ul>
 <li><code><a href="/en-US/docs/Web/JavaScript/Reference/Statements/for...in" title="JavaScript/Reference/Statements/for...in">for...in</a></code> - a similar statement that iterates over the property <em>names</em>.</li>
 <li><code><a href="/en-US/docs/Web/JavaScript/Reference/Statements/for...of" title="/en-US/docs/JavaScript/Reference/Statements/for...of">for...of</a></code> - a similar statement that iterates over the property <em>values</em> but there is some behavior that is different from <code>for each...in</code> statements.</li>
 <li><code><a href="/en-US/docs/JavaScript/Reference/Statements/for" title="JavaScript/Reference/Statements/for">for</a></code></li>
</ul>