If class found condition
<p>I need to check if an input field has no value then I'll append a notice. However if such notice has been already appended but another script I not need to do anything. </p>

<p>The only difference between my notice and a notice that could be added by another script is that my will have an extra class in it.</p>

<pre><code>// notice set by script
&lt;div class="noticeMessage"&gt;&lt;/div&gt;

// my Notice format
&lt;div class="noticeMessage myNotice"&gt;&lt;/div&gt;
</code></pre>

<p>So, how do I check is other notice has been set and it's not mine? </p>

<pre><code>if ($('#myField').val() == '' &amp;&amp; $('.noticeMessage').length == 0) {
   // add my notice      
}
</code></pre>
