Revision 809309 of do...while

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

<p>The <strong><code>do...while</code> statement</strong> creates a loop that executes a specified statement until the test condition evaluates to true. The condition is evaluated after executing the statement, resulting in the specified statement executing at least once.</p>

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

<pre class="syntaxbox">
do
   <em>statement</em>
while (<em>condition</em>);
</pre>

<dl>
 <dt><code>statement</code></dt>
 <dd>A statement that is executed at least once and is re-executed each time the condition evaluates to true. To execute multiple statements within the loop, use a {{jsxref("Statements/block", "block")}} statement (<code>{ ... }</code>) to group those statements.</dd>
</dl>

<dl>
 <dt><code>condition</code></dt>
 <dd>An expression evaluated after each pass through the loop. If <code>condition</code> evaluates to true, the <code>statement</code> is re-executed. When <code>condition</code> evaluates to false, control passes to the statement following the <code>do...while</code>.</dd>
</dl>

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

<h3 id="Using_do...while">Using <code>do...while</code></h3>

<p>In the following example, the <code>do...while</code> loop iterates at least once and reiterates until <code>i</code> is no longer less than 5.</p>

<pre class="brush: js">
var i = 0;
do {
   i += 1;
   console.log(i);
} while (i &lt; 5);
</pre>

<h2 id="Specifications">Specifications</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
  <tr>
   <td>ECMAScript 3rd Edition.</td>
   <td>Standard</td>
   <td>Initial definition.<br />
    Implemented in JavaScript 1.2</td>
  </tr>
  <tr>
   <td>{{SpecName('ES5.1', '#sec-12.6.1', 'do-while statement')}}</td>
   <td>{{Spec2('ES5.1')}}</td>
   <td>&nbsp;</td>
  </tr>
  <tr>
   <td>{{SpecName('ES6', '#sec-do-while-statement', 'do-while statement')}}</td>
   <td>{{Spec2('ES6')}}</td>
   <td>Trailing ; is now optional.</td>
  </tr>
 </tbody>
</table>

<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>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>IE6+</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</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>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

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

<ul>
 <li>{{jsxref("Statements/while", "while")}}</li>
 <li>{{jsxref("Statements/for", "for")}}</li>
</ul>