How does ajax verify username and password

This article mainly introduces ajax how to verify the user name and password, the article is very detailed, has a certain reference value, interested friends must read it!

The details are as follows

1.ajax body part

Var xmlrequest;function createXMLHttpRequest () {if (window.XMLHttpRequest) {xmlrequest=new XMLHttpRequest ();} else if (window.ActiveXObject) {try {xmlrequest=new ActiveXObject ("Msxm12.XMLHTTP");} catch (e) {try {xmlrequest=new ActiveXObject ("Microsoft.XMLHTTP") } catch (e) {} function login () {createXMLHttpRequest (); var user= document.getElementById ("yhm"). Value; var password= document.getElementById ("mm"). Value; if (user== "" | | password== "") {alert ("Please enter user name and password!"); return false;} var url = "check.php?user=" + user+ "& password=" + password Xmlrequest.open ("POST", url,true); xmlrequest.setRequestHeader ("Content-Type", "application/x-www-form-urlencoded"); xmlrequest.onreadystatechange = function () {if (xmlrequest.readyState = = 4) {if (xmlrequest.status==200) {var msg= xmlrequest.responseText; if (msg=='1') {alert ('wrong username or password!'); user= "; password="; return false } else {_ window.location.href= "index1.html";} xmlrequest.send ("user=" + user+ "& password=" + password);}

2.html code