Html code
| The code is as follows: |
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<Script src = "ajax. js"> </script>
<Form>
<Table>
<Tr>
<Td> user name: </td>
<Td> <input type = "text" id = "txt1" onKeyUp = "showHint (this. value)"> </td>
</Tr>
<Tr align = "center">
<Td colspan = "2"> <span id = "txtHint"> </span> </td>
</Tr>
</Table>
</Form> |
Js file code
| The code is as follows: |
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Var xmlHttp
Function showHint (str)
{
If (str. length = 0)
{
Document. getElementById ("txtHint"). innerHTML = ""
Return
}
XmlHttp = GetXmlHttpObject ()
If (xmlHttp = null)
{
Alert ("Browser does not support HTTP Request ")
Return
}
XmlHttp. onreadystatechange = stateChanged Var geturl = "conn. php? Q = "+ str
// Sid is to add a random number to prevent the cache technology from being enabled on the page ·
Geturl = geturl + "& sid =" + Math. random ()
Geturl = encodeURI (geturl );
Geturl = encodeURI (geturl );
XmlHttp. open ("GET", geturl, true)
XmlHttp. send (null)
}
Function stateChanged ()
{
If (xmlHttp. readyState = 4 | xmlHttp. readyState = "complete ")
{
Document. getElementById ("txtHint"). innerHTML = xmlHttp. responseText
}
}
Function GetXmlHttpObject ()
{
Var xmlHttp = null;
Try
{
// Firefox, Opera 8.0 +, Safari
XmlHttp = new XMLHttpRequest ();
}
Catch (e)
{
// Internet Explorer
Try
{
XmlHttp = new ActiveXObject ("Msxml2.XMLHTTP ");
}
Catch (e)
{
XmlHttp = new ActiveXObject ("Microsoft. XMLHTTP ");
}
}
Return xmlHttp;
} |
Php operations
| The code is as follows: |
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<? Php
$ Q = $ _ GET ["q"];
$ Q = urldecode ($ q ); If (strlen ($ q)> 0)
{
$ Conn = @ mysql_connect ("localhost", "root", "1010") or die ("MySql connection error ");
Mysql_select_db ("xin", $ conn );
Mysql_query ("set names 'utf8 '");
$ SQL = "SELECT username FROM message WHERE username = '$ Q '";
$ Query = mysql_query ($ SQL );
@ $ Row = mysql_fetch_array ($ query );
If (! Empty ($ row ['username'])
{
$ Response = "<font color = red> registered! </Font> ";
} Else
{
$ Response = "<font color = blue> Congratulations! Yes! </Font> ";
}
Echo $ response;
} ?> |
Finally, the database is provided.
| The code is as follows: |
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Drop database if exists 'sin ';
Create database 'sin '/*! 40100 default character set utf8 */;
USE 'sin ';
Create table 'message '(
'Id' int (11) not null auto_increment,
'Username' varchar (20) default NULL,
Primary key ('id ')
) ENGINE = InnoDB AUTO_INCREMENT = 2 default charset = utf8;
|
