只写一个表单，可以达到两个表单的效果

<form action="__URL__/lists" method="POST">
            <input type="hidden" name="flag" value="search">
            标题:<input type="text" name="title" value="" class="queryInput">
            文章分类:<select name="cate" class="querySelect">
                <option value="">请选择...</option>
                <volist name="alist" id="vo">
                    <option value="{$vo.id}">
                        <?php
                            for($i=0;$i<$vo['count']*3;$i++){
                                echo "&nbsp;";
                            }
                        ?>
                    {$vo.cname}{$vo.id}</option>
                </volist>
            </select>
            <input type="submit" value="查询" class="formbtn">
</form>

if($_POST['title']!=""){
            $Article = D("Article");
            $title = trim($_POST['title']);
            $lists = $Article->where("title='$title'")->select();
            $this->assign('lists',$lists);
            $this->display();
        }elseif($_POST['cate']!=""){
            $Article = D("Article");
            $cid = $_POST['cate'];
            echo $cid;
            $lists = $Article->where("cid=$cid")->select();
            $this->assign('lists',$lists);
            $this->display();
        }else{
。。。
}

用表单中的title和cate两个name分别是否为空来判断是提交的哪个单一表单。