Smarty combined with Ajax to implement non-refresh guestbook example

看了标题你也许要说，留言本，很基本的东东啊！谁不会啊，还要用Smarty，这不找累吗？别急，我要表达的是一种编程的思想和结构，而不是证明我做的东西多有意义，通过它相信对初学者学习Smarty和ajax有些启发。原本用ajax做的，可惜始终调试不成功，只好用手写JS来弄了，不过不要紧，还是有一定价值的。站点结构大家下了源代码自己看，代码不长，应该不会看烦^_^，听我慢慢道来。
     现在都PHP5了OO（面向对象）很流行了都，这里也不错过，首先来看下我们用OO来实现数据库操作和连接：
[php]
/**************************
页面：dbclass.php
作者：辉老大
功能：定义数据库操作类
**************************/
php
/**************************
页面：dbclass.php
作者：辉老大
功能：定义数据库操作类
**************************/
class db{
//创建构造函数，作用：数据库连接并选择相应数据库
public function __construct(){
require('config.inc.php');
mysql_connect($dbhost,$dbuser,$dbpassword) or die("error!");
mysql_query("SET NAMES 'GBK'");
mysql_select_db($dbname);
}
//执行SQL语句函数
public function query($sql){
return mysql_query($sql);
}
//取得结果集数组函数
public function loop_query($result){
return mysql_fetch_array($result);
}
//创建析构函数，作用：关闭数据库连接
public function __destruct(){
return mysql_close();
}
}
?> 
这个类有什么特点呢？首先介绍下__construct()是构造函数，啥是构造函数？通俗点讲就是类被实例化后就自动执行的函数，__destruct()是啥？是析构函数，它的作用就是在没有任何方法指向这个对象时，便自动销毁对象，里面一般包含一些收尾的操作，比如关闭文件，关闭数据库连接之类的方法，看到这你是不是明白一些了？没错！在类实例化的时候自动执行带有数据库连接方法的构造函数，在实例销毁的时候执行关闭数据库连接的析构函数，对于一些基本数据操作我们只要new一个$db对象，然后$db->query()...是不是很方便，当然，这只是一个简单的例子，你还可以继续扩展。来看看 config.inc.php里面是什么：
很容易对不对，感兴趣就接着看吧^_^，来看下模板文件：

php
/*************************
页面：config.inc.php
作者：辉老大
功能：数据库参数变量设定
$dbhost:主机名
$dbuser:连接帐户
$dbpassword:连接密码
$dbname:数据库名
*************************/
$dbhost = "localhost";
$dbuser = "root";
$dbpassword = "7529639";
$dbname = "testdb";
?> 

<{*这里显示留言内容*}>
<{section name=loop loop=$bookinfo}><{*循环显示留言*}>
用户名：<{$bookinfo[loop].username}> 内容：<{$bookinfo[loop].comment}>

<{/section}>

< ;td width="80" height="30" align="center">Username:

"
"
" " ;td height="120">



php
/***************************************** Title:Smarty combined with Ajax message board
Example Author:leehui1983(Hui Boss)
Page Name:index.php
Finish Date:2006-12-17
************************* ****************/

require('./libs/Smarty.class.php ');//Contains smarty class library
require('./inc/dbclass.php');//Contains databaseoperation class
$db = new db();//Generate database operation instance
$smarty = new Smarty(); //Instantiate smarty Object
$smarty->template_dir = "./templates";//Set template directory
$smarty-> compile_dir ="./templates_c"; //Set the compilation directory
$smarty->caching = false; / /Set cache method /************************************************ *********
Left and right boundary characters, the default is {}, but in actual applications it is easy to conflict with JavaScript
, so it is recommended to set it to <{}> or other.
*************************************************** ****/
$smarty->left_delimiter = "<{";
$smarty-> ;right_delimiter = "}>";
$smarty->assign('title','smarty combined with ajax to create a simple message board' ); //Replace template content
//Set the initial pagemessage content displayed by Smarty
$rt=$db->query(( "select * from bookinfo order by id desc"
); while($rs=$db->loop_query($rt
)){ $array[]=array("username"=>$rs['username'],"comment"=&g t; $rs['comment'
]);
} $smarty->assign("bookinfo", $array
); unset ($array);
//Destroy array variable $smarty->display("index.t pl");
//Compile and display the index.tpl template located under ./templates ?>
There are quite a lot of comments on the page examples. Please refer to the Smartymanual
This is So easy! ! Haha~~~~
Then it’s time to introduce ajax. Here we use a basic development framework to implement it. For knowledge about ajax, I suggest you take a look at the very popular online electronic tutorial Ajax Development Brief
var http_request=false;
function send_request(url){//Initialization, specify the processing function, the function to send the request
http_request=false;
//Start initializing the XMLHttpRequest object
if(window.XMLHttpRequest){//Mozilla browser
http_request=new XMLHttpRequest();
if(http_request.overrideMimeType){//Set MIME category
http_request.overrideMimeType("text/xml");
}
}
else if(window.ActiveXObject){//IE browser
try{
http_request=new ActiveXObject("Msxml2.XMLHttp");
}catch(e){
try{
http_request=new ActiveXobject("Microsoft.XMLHttp");
}catch(e){}
}
}
if(!http_request) {//Exception, failed to create object instance
window.alert("Failed to create XMLHttp object!");
return false;
}
http_request.>//Determine the request method, URL, and whether to execute the next code synchronously
http_request .open("GET",url,true);
http_request.send(null);
}
//Function that processes the returned information
function processrequest(){
if(http_request.readyState==4){//Judgement Object status
if(http_request.status==200){//The information has been returned successfully, start processing the information
document.getElementById(reobj).innerHTML=http_request.responseText;
}
else{//The page is not normal
alert( "The page you requested is abnormal! ");
}
}
}
function send(obj){
var f=document.book;
var username=f.username.value;
var comment=f.comment.value;
if(username== ""||comment==""){🎜 document.getElementById(obj).innerHTML="Please fill it out completely!";
return false;
}
else{
send_request('checkbookinfo.php?username='+username+'&comment='+comment);
reobj=obj;
}
}
This is how we click "Publish" button, the data will be processed asynchronously by the server, and asynchronous updates will be organized through JS. After sending a message, you will be able to see your message immediately instead of waiting for the traditional page to jump. So where is the data sent for processing? ?Look here:
php
/*****************************************
Title: Smarty combined with Ajax message board example
Author :leehui1983(Hui Boss)
Page Name:checkbookinfo.php
Finish Date :2006-12-17
*************************** **************/
header("Content-type: text/html;charset=GBK" );//Output encoding to avoid Chinese garbled characters
include('./inc/dbclass.php');//Include database operation classes
$ db=new db();//Generate database operation instance
$sql="insert into bookinfo values(0,'". $comment ."','".$username."')";
$db->query ($ sql);
$querysql="select * from bookinfo order by id desc";
$result =$db-> query($querysql);
while($rows=$db->loop_query( $result)){ //Print the message list for real-time updates
//$arr.="Username: {$rows['username']} Content: {$rows['comment']}

";
echo ' Username: '.$rows['username'].' Content: '.$rows [ 'comment'].'

';
}
//echo $arr;
?>
Well, insert the data first , in general The updated data is organized and displayed through JS, AJAX looks really good! That’s basically the introduction. I wonder if you have ever thought about what can be changed by adding an iframe? Yes! No refresh chat room, use your ability to achieve a look. This example uses OO, AJAX, and SMARTY. There are quite a lot of things. I hope you all like it. I have decided to submit this article to PHP Magazine. If you reprint it, please indicate the copyright. Thank you! Finally, here is the effect picture~~~~

The above has introduced an example of Smarty combined with Ajax to implement a non-refresh guestbook, including the relevant content. I hope it will be helpful to friends who are interested in PHP tutorials.