Ajax user uniqueness verification implementation code

Time:2022-1-3

Verify from the username user table in the database my:
checkusername.html:

Copy codeThe code is as follows:
<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd”>
<html xmlns=”http://www.w3.org/1999/xhtml”>
<head>
<meta http-equiv=”Content-Type” content=”text/html; charset=gb2312″ />
< title > Untitled Document < / Title >
</head>
<script language=”javascript”>
var xmlHttp;
function createXMLHttpRequest(){
if(window.ActiveXObject){
xmlHttp = new ActiveXObject(“microsoft.XMLHTTP”);
}
else if(window.XMLHttpRequest){
xmlHttp = new XMLHttpRequest();
}
}
function send_request(url,data){
createXMLHttpRequest();
xmlHttp.open(“POST”,url,true);
xmlHttp.onreadystatechange = check_lll;
xmlHttp.setRequestHeader(“CONTENT-TYPE”, “application/x-www-form-urlencoded”);
xmlHttp.send(“username=” + data);
}
function check_lll(){
if(xmlHttp.readyState == 4){
if(xmlHttp.status == 200){
alert(xmlHttp.responseText);
}
}
}
function check_username(){
var f = document.form1;
var username = f.username.value;
if(username == “”){
alert(“NULL”);
return false;
}
else{
send_request(“check_it.php”,username);
}
}
</script>
<body>
<form name=”form1″ method=”post” action=””>
<p>&nbsp;</p><p>
Name: < input type = “text” name = “username” / >
</p>
<input type=”button” value=”check it” onclick=”check_username()” />
<p>&nbsp;</p>
<p>&nbsp; </p>
</form>
</body>
</html>

check_it.php:

Copy codeThe code is as follows:
<?php
$username = $_POST[“username”];
$conn = mysql_connect(“localhost:3306″,”root”,”123″);
mysql_select_db(“my”,$conn);
$sql = “select * from username where username = ‘$username'”;
$result = mysql_query($sql,$conn);
$num = mysql_fetch_array($result);
if($num > 0){
printf(“can’t use”);
}
else{
printf(“It can use”);
}

?>

Recommended Today

Ios15 adaptation

Need immediate modification 1. Uinavigationbar, uitoolbar and uitabbar styles Uinavigationbar, uitoolbar and uitabbar need to use uibarappearance APIs to set colors. // UINavigationBar let navigationBarAppearance = UINavigationBarAppearance() navigationBarAppearance.backgroundColor = .red navigationController?.navigationBar.scrollEdgeAppearance = navigationBarAppearance navigationController?.navigationBar.standardAppearance = navigationBarAppearance // UIToolbar let toolBarAppearance = UIToolbarAppearance() toolBarAppearance.backgroundColor = .blue navigationController?.toolbar.scrollEdgeAppearance = toolBarAppearance navigationController?.toolbar.standardAppearance = toolBarAppearance // UITabBar let tabBarAppearance […]