php ajax user registration detection code_PHP tutorial

In fact, it only requires a simple implementation of ajax to detect user names. The formal point is to divide it into three files. I’ll keep it simple here:

First one: index.php

                                                                                                                                                                                                                                                                                                                                                                                  

Username*  ​ < br />

The second one requires js: ajax.js
[php]

var xmlHttp;

function createXMLHttpRequest()
{
If(window.XMLHttpRequest)
{
xmlHttp = new XMLHttpRequest();//mozilla browser
}
else if(window.ActiveXObject)
{
try
{
xmlHttp = new ActiveX0object("Msxml2.XMLHTTP");//Old version of IE
}
catch(e)
{}
try
{
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");//New version of IE
}
catch(e)
{}
if(!xmlHttp)
{
window.alert("Cannot create XMLHttpRequest object instance");
return false;
}
}
}

function startRequest(username)
{
createXMLHttpRequest();//Special Edition

xmlHttp.open("GET","ckuser.php?name="+username,true);

xmlHttp.onreadystatechange = handleStateChange;
xmlHttp.send(null);
}

function handleStateChange()
{
if(xmlHttp.readyState==4)
{
if(xmlHttp.status==200)
{
//alert("Response from server: " + xmlHttp.responseText);
if(xmlHttp.responseText == "true"){
document.getElementById("ckuser").innerHTML = 'This username has been registered';
}
else if(xmlHttp.responseText == "false")
{
document.getElementById("ckuser").innerHTML = 'Detection passed';
}
}
}
}

[/php]

The third file is the php file: ckuser.php

         require_once("conn.php");
$username = $_GET["name"];
          $query="select id from user where username='".$username."';";
          $res=mysql_query($query);
If(mysql_num_rows($res)!=0)
                                                 {
                 echo "true";
                       }else
                                                                                 echo "false";
                                                                                                          }

?>

The last one is the database link file conn.php

$conn=mysql_connect("localhost","root","l1314520") or die("Database server connection error".mysql_error());
Mysql_select_db("test",$conn) or die("Database access error".mysql_error());
Mysql_query("set character set gb2312");
Mysql_query("set names gb2312");
?>

http://www.bkjia.com/PHPjc/371914.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/371914.htmlTechArticleIn fact, it only needs to simply implement ajax to detect the user name. The formal point is to divide it into three files. Let me keep it simple here: the first one: index. php !DOCTYPE html PUBLIC -//W3C//DTD XHTML 1.0 Transitional//E...