PHP全栈学习笔记13

php与ajax技术

web2.0的到来，ajax逐渐成为主流，什么是ajax，ajax的开发模式，优点，使用技术。（ajax概述，ajax使用的技术，需要注意的 问题，在php应用ajax技术的应用）

什么是ajax，ajax的开发模式，优点。

ajax是由jesse james garrett创建的，是asynchronous javascript and xml，异步javascript和xml技术，ajax并不是一门新的语言或技术，它是javascript，xml，css，dom等多种技术的组合，可以实现客户端的异步请求操作，可以在不刷新页面下与服务器进行通信，从而减少了用户的等待时间。

ajax开发模式：
浏览器（客户端） http传输，http请求， web服务器 数据存储，后端处理，继承系统，服务器端。

客户端（浏览器）javascript调用，ajax引擎 http请求，http传输， web和xml服务器，数据存储，后端处理，继承系统（服务端）。

优点：减轻服务器的负担，可以把部分由服务器负担的工作转移到客户端上，无刷新更新页面，可以调用xml等外部数据，基于标准化的并被广泛支持的技术。

javascript是一种在web页面中添加动态脚本代码的解释性程序语言。

xmlhttprequest

ie浏览器把xmlhttp

var http_request = new activexobject("msxml2.xmlhttp");

var http_request = new activexobject("microsoft.xmlhttp");

mozailla,safari等其他浏览器

var http_request = new xmlhttprequest();

if(window.xmlhttprequest){
http_request = new xmlhttprequest();
}else if(window.activexobject){
 try{
 http_request = new activexobject("msxml2.xmlhttp");
 }catch(e){
 try{
 http_request = new activexobject("msxml2.xmlhttp");
}catch(e){
 try{
 http_request = new activexobject("microsoft.xmlhttp");
}catch(e){}
}
}

xmlhttprequest对象的常用方法：

open()方法用于设置进行异步请求目标的url

open("method", "url" [,asyncflag [,"username" [, "password"]]])

send()方法用于向服务器发送请求

send(content)

setrequestheader()方法

setrequestheader()方法为请求的http头设置值

setrequestheader("label","value")

label用于指定http头，value用于指定http头设置值

open()方法过后才能使用setrequestheader()方法

abort()方法
abort()方法用于停止当前异步请求

getallresponseheaders()方法
getallresponseheaders()方法用于以字符串形式完整的http头信息。

xmlhttprequest对象常用的属性
onreadystatechange 每个状态改变时都会触发这个事件处理器，通常会调用一个javascript函数。

readystate 请求的状态：

0 为未初始化
1 为正在下载
2 为已加载
3 在交互中
4 为完成

responsetext 服务器的响应，表示字符串

responsexml 服务器的响应，表示xml

status 返回服务器的http状态码
statustext 返回http状态码对应的文本

xml语言为可扩展的标记语言，提供了用于描述结构化数据的格式。xmlhttprequest对象与服务器交换的数据，通常采用xml格式。

dom为文档对象模型，为xml文档的解析定义了一组接口。

在php中应用ajax技术检测用户名

<script language="javascript">
var http_request = false;
function createrequest(url) {
    //初始化对象并发出xmlhttprequest请求
    http_request = false;
    if (window.xmlhttprequest) {                                        //mozilla等其他浏览器
        http_request = new xmlhttprequest();
        if (http_request.overridemimetype) {
            http_request.overridemimetype("text/xml");
        }
    } else if (window.activexobject) {                              //ie浏览器
        try {
            http_request = new activexobject("msxml2.xmlhttp");
        } catch (e) {
            try {
                http_request = new activexobject("microsoft.xmlhttp");
           } catch (e) {}
        }
    }
    if (!http_request) {
        alert("不能创建xmlhttp实例!");
        return false;
    }
    http_request.onreadystatechange = alertcontents;                     //指定响应方法
    
    http_request.open("get", url, true);                                 //发出http请求
    http_request.send(null);
}
function alertcontents() {                                               //处理服务器返回的信息
    if (http_request.readystate == 4) {
        if (http_request.status == 200) {
            alert(http_request.responsetext);
        } else {
            alert('您请求的页面发现错误');
        }
    }
}
</script>
<script language="javascript">
function checkname() {
    var username = form1.username.value;
    if(username=="") {
        window.alert("请填写用户名!");
        form1.username.focus();
        return false;
    }
    else {
        createrequest('checkname.php?username='+username+'&nocache='+new date().gettime());
    }
}
</script>

<?php
    header('content-type: text/html;charset=gb2312');       //指定发送数据的编码格式为gb2312
    $link=mysql_connect("localhost","root","root");
    mysql_select_db("db_database",$link);
    $gb2312string=iconv( 'utf-8', 'gb2312//ignore' , $requestajaxstring);           //ajax中先用encodeuricomponent对要提交的中文进行编码
    mysql_query("set names gb2312");
    $username=$_get[username];
    $sql=mysql_query("select * from tb_user where name='".$username."'");
    $info=mysql_fetch_array($sql);
    if ($info){
        echo "很报歉!用户名[".$username."]已经被注册!";
    }else{
        echo "祝贺您!用户名[".$username."]没有被注册!";
    }
?>

类别添加

<script language="javascript">
var http_request = false;
function createrequest(url) {
    //初始化对象并发出xmlhttprequest请求
    http_request = false;
    if (window.xmlhttprequest) {                                        //mozilla等其他浏览器
        http_request = new xmlhttprequest();
        if (http_request.overridemimetype) {
            http_request.overridemimetype("text/xml");
        }
    } else if (window.activexobject) {                              //ie浏览器
        try {
            http_request = new activexobject("msxml2.xmlhttp");
        } catch (e) {
            try {
                http_request = new activexobject("microsoft.xmlhttp");
           } catch (e) {}
        }
    }
    if (!http_request) {
        alert("不能创建xmlhttp实例!");
        return false;
    }
    http_request.onreadystatechange = alertcontents;                     //指定响应方法
    
    http_request.open("get", url, true);                                 //发出http请求
    http_request.send(null);
}
function alertcontents() {                                               //处理服务器返回的信息
    if (http_request.readystate == 4) {
        if (http_request.status == 200) {
            sort_id.innerhtml=http_request.responsetext;                //设置sort_id html文本替换的元素内容
        } else {
            alert('您请求的页面发现错误');
        }
    }
}
</script>
<script language="javascript">
function checksort() {
    var txt_sort = form1.txt_sort.value;
    if(txt_sort=="") {
        window.alert("请填写文章类别!");
        form1.txt_sort.focus();
        return false;
    }
    else {
        createrequest('checksort.php?txt_sort='+txt_sort);
    }
}
</script>

<?php
    $link=mysql_connect("localhost","root","root");
    mysql_select_db("db_database",$link);
    $gb2312string=iconv( 'utf-8', 'gb2312//ignore',$requestajaxstring);         //ajax中先用encodeuricomponent对要提交的中文进行编码
    mysql_query("set names gb2312");
    $sort=$_get[txt_sort];
    mysql_query("insert into tb_sort(sort) values('$sort')");
    header('content-type: text/html;charset=gb2312');       //指定发送数据的编码格式为gb2312
?>
<table border="0" cellpadding="0" cellspacing="0">
  <tr>
    <td>
    <select name="select" >
    <?php
        $link=mysql_connect("localhost","root","root");
        mysql_select_db("db_database23",$link);
        $gb2312string=iconv( 'utf-8', 'gb2312//ignore' , $requestajaxstring);           //ajax中先用encodeuricomponent对要提交的中文进行编码
        mysql_query("set names gb2312");
        $sql=mysql_query("select distinct * from tb_sort group by sort");
        $result=mysql_fetch_object($sql);
        do{
            header('content-type: text/html;charset=gb2312');       //指定发送数据的编码格式为gb2312
    ?>
    <option value="<?php echo $result->sort;?>" selected><?php echo $result->sort;?></option>
    <?php
        }while($result=mysql_fetch_object($sql));
    ?>
    </select>

xml基础技术

了解xml，使用simplexml解析文档的方法
遍历xml文档，修改，保存xml，创建xml文档的方法

xml语法
xml文档结构，xml声明，处理指令，注解，xml元素，xml属性，使用cdata标记，xml命令空间。

xml文档结构

<?xml version="1.0" encoding="gb2312" standalone="yes"?>

<?xml-stylesheet type="text/css" href="111.css"?>

xml声明

<?xml version="1.0" encoding="gb2312" standalone="yes"?>

处理指令

<?xml-stylesheet type = "text/css" href="111.css"?>

<?处理指令名 处理执行信息?>

xml-stylesheet：样式表单处理指令
type="text/css"：设定了文档所使用的样式是css
href="111.css"：设定了样式文件的地址

xml属性

<标签 属性名="属性值" 属性名=""…>内容</标签＞

simplexml
创建simplexml对象
simplexml_load_file()函数，将指定的文件解析到内存中
simplexml_load_string()函数，将创建的字符串解析到内存当中
simplexml_load_date()函数，将一个使用dom函数创建的domdocument对象导入到内存当中

遍历所有子元素
children()方法和foreach循环语句可以遍历所有子节点元素

遍历所有属性
simplexml对象中的attributes()方法

<?xml version="1.0" encoding="gb2312"?>
<exam>

</exam>

<?php
header('content-type:text/html;charset=utf-8');
?>

<?php
/*  第一种方法  */
$xml_1 = simplexml_load_file("5.xml");
print_r($xml_1);
/*  第二种方法  */
$str = <<<xml
<?xml version='1.0' encoding='gb2312'?>
<object>
    <computerbook>
        <title>php</title>
    </computerbook>
</object>
xml;
$xml_2 = simplexml_load_string($str);
echo '<br>';
print_r($xml_2);
/*  第三种方法  */
$dom = new domdocument();
$dom -> loadxml($str);
$xml_3 = simplexml_import_dom($dom);
echo '<br>';
print_r($xml_3);
?>

<?php
header('content-type:text/html;charset=utf-8');
?>
<style type="text/css">

<?php
$str = <<<xml
<?xml version='1.0' encoding='gb2312'?>
<object>
    <book>
        <computerbook>php</computerbook>
    </book>
    <book>
        <computerbook>php</computerbook>
    </book>
</object>
xml;
$xml = simplexml_load_string($str);
foreach($xml->children() as $layer_one){
    print_r($layer_one);
    echo '<br>';
    foreach($layer_one->children() as $layer_two){
        print_r($layer_two);
        echo '<br>';
    }
}
?>

<?php
$str = <<<xml
<?xml version='1.0' encoding='gb2312'?>
<object name='commodity'>
    <book type='computerbook'>
        <bookname name='22'/>
    </book>
    <book type='historybook'>
        <booknanme name='111'/>
    </book>
</object>
xml;
$xml = simplexml_load_string($str);
foreach($xml->children() as $layer_one){
    foreach($layer_one->attributes() as $name => $vl){
        echo $name.'::'.$vl;
    }
    echo '<br>';
    foreach($layer_one->children() as $layer_two){
        foreach($layer_two->attributes() as $nm => $vl){
            echo $nm."::".$vl;
        }
        echo '<br>';
    }
}
?>

<?php
    header('content-type:text/html;charset=utf-8');
?>

<?php
$str = <<<xml
<?xml version='1.0' encoding='gb2312'?>
<object name='商品'>
    <book>
        <computerbook>p123</computerbook>
    </book>
    <book>
        <computerbook name='456'/>
    </book>
</object>
xml;
$xml = simplexml_load_string($str);
echo $xml[name].'<br>';
echo $xml->book[0]->computerbook.'<br>';
echo $xml->book[1]->computerbook['name'].'<br>';
?>

<?php
header('content-type:text/html;charset=utf-8');
$str=<<<xml
<?xml version='1.0' encoding='gb2312'?>
<object name='商品'>
    <book>
        <computerbook type='12356'>123</computerbook>
    </book>
</object>
xml;

$xml = simplexml_load_string($str);
echo $xml[name].'<br />';
$xml->book->computerbook['type'] = iconv('gb2312','utf-8','php123');
$xml->book->computerbook = iconv('gb2312','utf-8','php456');
echo $xml->book->computerbook['type'].' => ';
echo $xml->book->computerbook;
?>

<?php
$xml = simplexml_load_file('10.xml');
$xml->book->computerbook['type'] = iconv('gb2312','utf-8','php1');
$xml->book->computerbook = iconv('gb2312','utf-8','php2');
$modi = $xml->asxml();
file_put_contents('10.xml',$modi);
$str = file_get_contents('10.xml');
echo $str;
?>

<?php
    //message_xml类，继承php5的domdocument类
    class message_xml extends domdocument{
    //属性
    private $root;
    //方法
    //构造函数
    public function __construct() {
        parent:: __construct();
    //创建或读取存储留言信息的xml文档message.xml
    if (!file_exists("message.xml")){
        $xmlstr = "<?xml version='1.0' encoding='gb2312'?><message></message>";
        $this->loadxml($xmlstr);
        $this->save("message.xml");
    }
    else
        $this->load("message.xml");
}
public function add_message($user,$address){  //添加数据
    $root = $this->documentelement;
    //获取留言消息
    $admin_id =date("ynjhis");
    $node_admin_id= $this->createelement("admin_id");
    $text= $this->createtextnode(iconv("gb2312","utf-8",$admin_id));
    $node_admin_id->appendchild($text);
    
    $node_user = $this->createelement("user");
    $text  = $this->createtextnode(iconv("gb2312","utf-8",$user));
    $node_user->appendchild($text);
    
    $node_address = $this->createelement("address");
    $text= $this->createtextnode(iconv("gb2312","utf-8",$address));
    $node_address->appendchild($text);

    $node_record = $this->createelement("record");
    $node_record->appendchild($node_admin_id);
    $node_record->appendchild($node_user);
    $node_record->appendchild($node_address);
    //加入到根结点下
    $root->appendchild($node_record);
    $this->save("message.xml");  
    echo "<script>alert('添加成功');location.href='".$_server['php_self']."'</script>";
}
public function delete_message($admin_id){  //删除数据
    $root = $this->documentelement;
    $xpath = new domxpath($this);
    $node_record= $xpath->query("//record[admin_id='$admin_id']");
    $root->removechild($node_record->item(0));
    $this->save("message.xml");
    echo "<script>alert('删除成功');location.href='".$_server['php_self']."'</script>";
}

public function show_message(){  //读取数据
    $root=$this-documentelement;
    $xpath=new domxpath($this);
    
    $node_record=$this->getelementsbytagname("record");
    $node_record_length=$node_record->length;
    print"<table width='506' bgcolor='#ffffcc'><tr>";
    print"<td width='106' height='22' align='center'>";
    print"<b>用户名</b>";
    print"</td><td width='400' align='center'>";
    print"<b>留言信息</b></td></tr>";

    for($i=0;$i<$node_record->length;$i++){
        $k=0;
        foreach($node_record->item($i)->childnodes as $articles){
           $field[$k]=iconv("utf-8","gb2312",$articles->textcontent);
            $k++;
    }
    print"<table width='506' bgcolor='#ffffcc'><tr>";
    print"<td width='100' height='22' align='center'>";
    print"$field[1]";
    print"</td><td width='300' align='left'>";
    print"$field[2]";
    print"</td><td width='100' align='center'>";
    print"<a href='?action=delete_message&admin_id=$field[0]'>删除</a></td>";
    print"</tr></table>"; 
    }}
    public function post_message(){
        print "<table width='506' bgcolor='#ffffcc'><form method='post' action='?action=add_message'>";
        print "<tr><td  width='106'height='22'>&nbsp;&nbsp;&nbsp;&nbsp;用户名：</td><td><input type=text name='user' size=50></td></tr>";
        print "<tr><td width='106' height='22'>&nbsp;&nbsp;&nbsp;&nbsp;留言信息：</td><td width='400'><textarea name='address' cols='48' rows='5' id='address'></textarea></td></tr>";
        print "<tr><td width='106' height='30'>&nbsp;&nbsp;<input type='submit' value='添加数据'></td><td align='right'><a href=?action=show_message>查看数据</a>&nbsp;&nbsp;&nbsp;&nbsp;</td></tr></form></table>";
    }

}
?>

<html>                                                                                                                           
    <head>                                                                                                                  
    <title>定义一个php读取xml类</title>                                                                                        
        <style>
        td,body{font-size:12px}
        a:link {
    text-decoration: none;
}
a:visited {
    text-decoration: none;
}
a:hover {
    text-decoration: none;
}
a:active {
    text-decoration: none;
}
</style>                                                                                      
    <meta http-equiv="content-type" content="text/html; charset=gb2312"></head>                                                                                                                        
<body>                                                                                                                         
<table width=506 height=50 border=0 cellpadding=0 cellspacing=0 bgcolor="#33be6b">                                
                                                                                                                          
        <tr>                                                                                                                         
          <td width="506" height=50 valign="bottom" background="title.gif"><table width="506">
            <tr>
              <td height="24" align="right" scope="col">&nbsp;&nbsp;<a href=?action=post_message>添加数据</a>&nbsp;&nbsp;&nbsp;</td>
            </tr>
          </table></td>
        </tr>  
        <?php                                                                                       
        $hawkxml = new message_xml;     
        $action ="";      
        if(isset($_get['action']))     
              $action = $_get['action'];                                                                                       
        switch($action){                                                                                            
            case "show_message":        //查看                                                                               
                $hawkxml->show_message();                                                                         
                break;                                                                                                     
            case "post_message":        //提交                                                                               
                $hawkxml->post_message();                                                                       
                break;                                                                                                      
            case "add_message":          //添加                                                                            
                $hawkxml->add_message($_post['user'],$_post['address']);                                             
                break;    
            case "delete_message":      //删除
                $hawkxml->delete_message($_get['admin_id']);
                break;
        }                                                                                                
       ?>   
</table>                                                                                                                   
</body>                                                                                                                      
</html>                                                                                                                        

<?php
    //message_xml类，继承php5的domdocument类
    class message_xml extends domdocument{
    //属性
    private $root;
    //方法
    //构造函数
    public function __construct() {
        parent:: __construct();
    //创建或读取存储留言信息的xml文档message.xml
    if (!file_exists("message.xml")){
        $xmlstr = "<?xml version='1.0' encoding='gb2312'?><message></message>";
        $this->loadxml($xmlstr);
        $this->save("message.xml");
    }
    else
        $this->load("message.xml");
}
public function add_message($user,$address){  //添加数据
    $root = $this->documentelement;
    //获取留言消息
    $admin_id =date("ynjhis");
    $node_admin_id= $this->createelement("admin_id");
    $text= $this->createtextnode(iconv("gb2312","utf-8",$admin_id));
    $node_admin_id->appendchild($text);
    
    $node_user = $this->createelement("user");
    $text  = $this->createtextnode(iconv("gb2312","utf-8",$user));
    $node_user->appendchild($text);
    
    $node_address = $this->createelement("address");
    $text= $this->createtextnode(iconv("gb2312","utf-8",$address));
    $node_address->appendchild($text);

    $node_record = $this->createelement("record");
    $node_record->appendchild($node_admin_id);
    $node_record->appendchild($node_user);
    $node_record->appendchild($node_address);
    //加入到根结点下
    $root->appendchild($node_record);
    $this->save("message.xml");  
    echo "<script>alert('添加成功');location.href='".$_server['php_self']."'</script>";
}

public function show_message(){  //读取数据
    $root=$this-documentelement;
    $xpath=new domxpath($this);
    
    $node_record=$this->getelementsbytagname("record");
    $node_record_length=$node_record->length;
    print"<table width='506' bgcolor='#ffffcc'><tr>";
    print"<td width='106' height='22' align='center'>";
    print"<b>用户名</b>";
    print"</td><td width='400' align='center'>";
    print"<b>留言信息</b></td></tr>";

    for($i=0;$i<$node_record->length;$i++){
        $k=0;
        foreach($node_record->item($i)->childnodes as $articles){
           $field[$k]=iconv("utf-8","gb2312",$articles->textcontent);
            $k++;
    }
    print"<table width='506' bgcolor='#ffffcc'><tr>";
    print"<td width='100' height='22' align='center'>";
    print"$field[1]";
    print"</td><td width='400' align='left'>";
    print"$field[2]";
    print"</td>";
    print"</tr></table>"; 
    }}
    public function post_message(){
        print "<table width='506' bgcolor='#ffffcc'><form method='post' action='?action=add_message'>";
        print "<tr><td  width='106'height='22'>&nbsp;&nbsp;&nbsp;&nbsp;用户名：</td><td><input type=text name='user' size=50></td></tr>";
        print "<tr><td width='106' height='22'>&nbsp;&nbsp;&nbsp;&nbsp;留言信息：</td><td width='400'><textarea name='address' cols='48' rows='5' id='address'></textarea></td></tr>";
        print "<tr><td width='106' height='30'>&nbsp;&nbsp;<input type='submit' value='添加数据'></td><td align='right'><a href=?action=show_message>查看数据</a>&nbsp;&nbsp;&nbsp;&nbsp;</td></tr></form></table>";
    }

}
?>
<html>                                                                                                                           
    <head>
    <title>使用xml来存储少量的数据</title>                                                                                 
    <style>
    td,body{font-size:12px}
    a:link {
    text-decoration: none;
}
a:visited {
    text-decoration: none;
}
a:hover {
    text-decoration: none;
}
a:active {
    text-decoration: none;
}
</style>                                                                                      
    <meta http-equiv="content-type" content="text/html; charset=gb2312"></head>                                                                                                                        
<body>                                                                                                                         
<table width=506 height=50 border=0 cellpadding=0 cellspacing=0 bgcolor="#33be6b">                                
                                                                                                                          
        <tr>                                                                                                                         
          <td width="506" height=50 valign="bottom" background="title.gif"><table width="506">
            <tr>
              <td height="24" align="right" scope="col">&nbsp;&nbsp;<a href=?action=post_message>添加数据</a>&nbsp;&nbsp;&nbsp;</td>
            </tr>
          </table></td>
        </tr>  
        <?php                                                                                       
        $hawkxml = new message_xml;     
        $action ="";      
        if(isset($_get['action']))     
              $action = $_get['action'];                                                                                       
        switch($action){                                                                                            
            case "show_message":        //查看                                                                               
                $hawkxml->show_message();                                                                         
                break;                                                                                                     
            case "post_message":        //提交                                                                               
                $hawkxml->post_message();                                                                       
                break;                                                                                                      
            case "add_message":          //添加                                                                            
                $hawkxml->add_message($_post['user'],$_post['address']);                                             
                break;    }                                                                                                
         ?>
</table>                                                                                                                   
</body>                                                                                                                      
</html>                                                                                                                        

结言

好了，欢迎在留言区留言，与大家分享你的经验和心得。

感谢你学习今天的内容，如果你觉得这篇文章对你有帮助的话，也欢迎把它分享给更多的朋友，感谢。

感谢！承蒙关照！您真诚的赞赏是我前进的最大动力！