 <p>Try this:</p> <p><a href="http://jsfiddle.net/edz8B/1/" rel="nofollow">DEMO</a></p> <p>JS</p> <pre><code>function setChk(value){ var chk = document.getElementById('check1'); chk.checked = (value != 'null'); } </code></pre> <p>HTML</p> <pre><code>&lt;table&gt; &lt;tr&gt; &lt;td&gt; &lt;input type="checkbox" name="check1" id="check1"/&gt;Process 1:&lt;/td&gt; &lt;td&gt; &lt;select id="process1" name="process1" onchange="setChk(this.value);"&gt; &lt;option value="null"&gt;--Select Process--&lt;/option&gt; &lt;option value="NameA"&gt;NameA&lt;/option&gt; &lt;option value="NameB"&gt;NameB&lt;/option&gt; &lt;option value="NameC"&gt;NameC&lt;/option&gt; &lt;/select&gt; &lt;/td&gt; &lt;/tr&gt; &lt;/table&gt; </code></pre>