php check if at least two checkbox is checked and display a message to user
<pre><code>&lt;div class='container'&gt;&lt;label for='vehicle'&gt;Vehicle:&lt;/label&gt;&lt;br/&gt;
 &lt;span id='contactus_vehicle_errorloc' class='error'&gt;&lt;/span&gt;
&lt;input type="checkbox" name="vehicle" id="bike" value=&lt;?php echo $formproc-&gt;SafeDisplay('bike') ?&gt; /&gt; I have a bike&lt;br /&gt;
&lt;input type="checkbox" name="vehicle" id="car" value=&lt;?php echo $formproc-&gt;SafeDisplay('car') ?&gt; /&gt; I have a car &lt;br /&gt;
&lt;input type="checkbox" name="vehicle" id="motorbike" value=&lt;?php echo $formproc-&gt;SafeDisplay('motorbike') ?&gt; /&gt; I have a motorbike &lt;br/&gt;
&lt;input type="checkbox" name="vehicle" id="plane" value=&lt;?php echo $formproc-&gt;SafeDisplay('plane') ?&gt; /&gt; I have a plane &lt;br/&gt;
&lt;input type="checkbox" name="vehicle" id="papaki" value=&lt;?php echo $formproc-&gt;SafeDisplay('papaki') ?&gt; /&gt; I have a papaki &lt;br/&gt;
&lt;/div&gt;
</code></pre>
