title: Show alert() if no checkbox is selected
body: <p>After click the button "Delete", How to display an alert if none of checkbox is selected.
  My html form
      
      </p>
  
  <pre><code>&lt;form name="Delete" method="post" action="DeleteAdministrator"&gt;
                  &lt;table width="800px" cellpadding="5" style="color:black; border-top:1px solid #ccc;" border="0"&gt;
                  &lt;/table&gt;
                      &lt;div id="container"&gt;
                      &lt;div id="demo_jui"&gt;
                      &lt;table id="adminList" class="display" cellpadding="0" cellspacing="0" border="0" style="font-size:12px;" &gt;
                      &lt;thead id="headed"&gt;
                      &lt;tr&gt;
                          &lt;th  align="center" title="Select"&gt;Select&lt;/th&gt;
                          &lt;th align="center" title="Email Address"&gt;Email Address&lt;/th&gt; 
                          &lt;/tr&gt;
                      &lt;/thead&gt;
                      &lt;tbody&gt;&lt;/tbody&gt;
                      &lt;/table&gt;
                      &lt;/div&gt;
                      &lt;/div&gt;
                      &lt;table id="footed"&gt;
                          &lt;tr&gt;
                              &lt;td colspan="2"&gt;
                                  &lt;a href="#"&gt;&lt;img src="images/Delete.png" style="border:none;" onClick="javascript:Go()"
                                  onmouseover="this.src='images/Delete_Hover.png'" onmouseout="this.src='images/Delete.png'"/&gt;&lt;/a&gt;
                                  &amp;nbsp;&amp;nbsp;&amp;nbsp;
                                  &lt;a href="#"&gt;&lt;img src="images/Reset.png" style="border:none;" onClick="javascript:clearForm()"
                                  onmouseover="this.src='images/Reset_Hover.png'" onmouseout="this.src='images/Reset.png'"/&gt;&lt;/a&gt;
                              &lt;/td&gt;
                          &lt;/tr&gt;
                      &lt;/table&gt;
                  &lt;/form&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>The checkbox value will be retrieved in table. When I test it, 
  When checkbox is select or non-select, it still alert "Please select to delete admin" </p>
  
  <p>In function <code>Go()</code>, is the way validate <code>document.Delete.delAdlist[i].checked</code> correct? Thank you</p>
  
  <pre><code>&lt;script language="JavaScript"&gt;                      
      var running = 0;
      function Go() {
          var f = document.forms[0];
          for (i = 0; i &lt; document.Delete.delAdlist.length) {
              if (!document.Delete.delAdlist[i].checked) {
                  alert("Please select to delete admin.");
                  return false;
              }
              else {
                  f.submit();
                  return true;
              }
          }  
          f.submit();
          running++;
      }                               
  &lt;/script&gt;
  </code></pre>