一点代码，体验严谨


    public function searchnews() {
    $type = $this->input->post("type");
    $keyword = $this->input->post("keyword");

    if(empty($keyword)){
        echo '<script type="text/javascript">';
        echo "alert('搜索的关键词，不能为空！');";
        echo "</script>";

        $this->listnews();
    }else{

        if($type=="title"){
            $newslist = ORM :: factory('news')->like("title",$keyword)->find_all();
        }elseif($type=="content"){
            $newslist = ORM :: factory('news')->like("content",$keyword)->find_all();
        }else{
            $newslist = ORM :: factory('news')->orlike(array("title"=>$keyword,"content"=>$keyword))->find_all();
        }

        $news = new View('admin/searchNews');
        $news->newslist = $newslist;
        $this->template->content = $news;
    }
    
}

以上代码，比较严谨。关键字为空时，可以正常alert。以下代码，看似没有什么问题，但是却不能正常提示。


	public function searchnews() {
	$type = $this->input->post("type");
	$keyword = $this->input->post("keyword");

	if(empty($keyword)){
		echo '<script type="text/javascript">';
		echo "alert('搜索的关键词，不能为空！');";
		echo "</script>";

		$this->listnews();
	}

	if($type=="title"){
		$newslist = ORM :: factory('news')->like("title",$keyword)->find_all();
	}elseif($type=="content"){
		$newslist = ORM :: factory('news')->like("content",$keyword)->find_all();
	}else{
		$newslist = ORM :: factory('news')->orlike(array("title"=>$keyword,"content"=>$keyword))->find_all();
	}

	$news = new View('admin/searchNews');
	$news->newslist = $newslist;
	$this->template->content = $news;

}

看来还是要在if里把判断包含全面了才安心啊。