Simple Example: AJAX combined with PHP code to achieve logon result code _ php instance

It is relatively simple to implement the login function through ajax + php. This is a simple example. Fixed characters can be read from the database in practical applications. HTML section:



Function postRequest (strURL ){
Var xmlHttp;
If (window. XMLHttpRequest) {// For Mozilla, Safari ,...
Var xmlHttp = new XMLHttpRequest ();
}
Else if (window. ActiveXObject) {// For Internet Explorer
Var xmlHttp = new ActiveXObject ("Microsoft. XMLHTTP ");
}
XmlHttp. open ('post', strURL, true );
XmlHttp. setRequestHeader ('content-type', 'application/x-www-form-urlencoded ');
XmlHttp. onreadystatechange = function (){
If (xmlHttp. readyState = 4 ){
Updatepage (xmlHttp. responseText );
}
}
XmlHttp. send (strURL );
}

Function updatepage (str ){
If (str = "yes "){
Alert ("Welcome User ");
} Else {
Alert ("Invalid Login! Please try again! ");
}
}

Function call_login (){
Var username = parameter Doc ument. f1.username. value;
Var password = parameter Doc ument. f1.password. value;
Var url = "login. php? Username = "+ username +" & password = "+ password;
PostRequest (url );
}













PHP script login. php:

$ Username = $ _ GET ["username"];
$ Password = $ _ GET ["password"];
If ($ username = "admin" & $ password = "admin "){
Echo "yes ";
} Else {
Echo "No ";
}
?>