Validate check box to be checked atleast one using javascript

i'm a beginner for java script please solve this. validate this checkbox using javascript.

<td>
                                   your favourite programming languages
                               </td>
                               <td>
                                   <?php
                                   $favarr = array("Java", "Php", "C++", "dotnet");
                                   foreach ($favarr as $fa) {
                                       $checked = "";
                                       if (in_array($fa, $fav)) {
                                           $checked = "checked";
                                       }
                                       echo '<input type="checkbox" value="' . $fa . '" name="fav[]"' . $checked . '> <label id="fav">' .$fa. '</label>' ;
                                   }
                                   //}
                                   ?>

                               </td>