ผมเขียนให้แบบง่าย ๆ น่ะครับ
Code (ajax1.php)
<html>
<body>
<script language="JavaScript">
var HttPRequest = false;
function CallPOSTRequest(url,parameters) {
HttPRequest = false;
if (window.XMLHttpRequest) { // Mozilla, Safari,...
HttPRequest = new XMLHttpRequest();
if (HttPRequest.overrideMimeType) {
HttPRequest.overrideMimeType('text/html');
}
} else if (window.ActiveXObject) { // IE
try {
HttPRequest = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
HttPRequest = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {}
}
}
if (!HttPRequest) {
alert('Cannot create XMLHTTP instance');
return false;
}
HttPRequest.onreadystatechange = alertContener;
HttPRequest.open('POST', url, true);
HttPRequest.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
HttPRequest.setRequestHeader("Content-length", parameters.length);
HttPRequest.setRequestHeader("Connection", "close");
HttPRequest.send(parameters);
}
function alertContener() {
if (HttPRequest.readyState == 4) {
if (HttPRequest.status == 200) {
result = HttPRequest.responseText;
document.getElementById('myspan').innerHTML = result;
} else {
//alert('There was a problem with the request.');
result = HttPRequest.responseText;
document.getElementById('myspan').innerHTML = result;
}
}
}
function SubmitContent(value) {
document.getElementById('myspan').style.visibility = 'hidden';
document.getElementById('myspan').style.visibility = 'visible';
var poststr = "User=" + encodeURI(document.getElementById('txtUser').value);
CallPOSTRequest('ajax2.php',poststr);
}
</script>
<form id="myform" action="" method="post">
<span id="myspan"></span><br>
<input type="text" name="txtUser">
<input name="Check" type="button" id="Check" value="Check" OnClick="JavaScript:SubmitContent();">
</form>
</body>
</html>
Code (ajax2.php)
<?
//************ MySQL Check *************//
mysql_connect("localhost","root","root");
mysql_select_db("mydatabase");
$strSQL = "SELECT * FROM user WHERE UserName = '".trim($_POST["User"])."' ";
$objQuery = mysql_query($strSQL);
$intRows = mysql_num_rows($objQuery);
if($intRows>0)
{
echo "[".$_POST["User"]."] already exist.";
}
?>
รันไฟล์ ajax1.php ครับ และก็สร้าง table user ด้วยครับ
