글작성시 필수항목을 안했을때 작성했던것이 초기화 안되는 방법??

<?php if ($is_category) { ?>
            <dl>
                <dt>
                    <label for="ca_name"><span class="needs">*</span> 정부지원사업</label>
                </dt>
                <dd>
                    <? $cate_menu = explode("|",$board[bo_category_list]); 
                        for ($c=0, $cnt=count($cate_menu); $c<$cnt; $c++) {
                            if ($write[ca_name] == $cate_menu[$c]){ 
                                $checked[$c] = "checked"; 
                            } else { 
                                $checked[$c] = ""; 
                            }
                            echo "<input type='radio' id='ca_name$c' name='ca_name' value='$cate_menu[$c]' ".$checked[$c].">";
                            echo "<label for='ca_name$c'>".$cate_menu[$c]."</label>";
                        } 
                    ?>
                </dd>
            </dl>
            <?php } ?>

<input type="text" name="wr_subject" value="<?php echo $write[wr_subject] ?>" id="wr_subject" required class="frm_input required" size="30" maxlength="20" >