Untitled

<html>
<head>
<title> Login Form</title>
<script>
     function validate()
    {
        var username = document.getElementById("username").value;
        var password = document.getElementById("password").value;
        var loginlist = { "User": {
                                "userlist":[{"username":"usr1", "password":"a123"},{"username":"usr2", "password":"a123"},{"username":"usr3", "password":"a123"}],
                                "ID":1
                            },
                            "Admin": {
                                    "adminlist":[{"username":"admin1", "password":"b123"},{"username":"admin2", "password":"b123"},{"username":"admin3", "password":"b123"}],
                                    "ID":2
                            },
                            "Supplier": {
                                    "supplierlist":[{"username":"sup1", "password":"c123"},{"username":"sup2", "password":"c123"},{"username":"sup3", "password":"c123"}],
                                    "ID":1
                            }
        };
        var logged = false;
        if(loginlist[0].User.ID === 1){
            for(var i =0; i < loginlist[0].User.userlist.length; i++){
                if(username == loginlist[0].User.userlist[i].username && password == loginlist[0].User.userlist[i].password){
                    logged= true;
                }
            }
            if(logged)
            alert("User login");

            else
            alert("User login fail");

        }
        else if(loginlist[0].Admin.ID === 2){
            for(var j =0; j < loginlist[0].Admin.adminlist.length; j++){
                if(username == loginlist[0].Admin.adminlist[j].username && password == loginlist[0].Admin.adminlist[j].password){
                    logged= true;
                }
            }
            if(logged)
            alert("Admin login");

            else
            alert("admin login fail");

        }
        else{
            for(var k =0; k < loginlist[0].Supplier.supplierlist.length; k++){
                if(username == loginlist[0].Supplier.supplierlist[k].username && password == loginlist[0].Supplier.supplierlist[k].password){
                    logged= true;
                }
            }
            if(logged)
            alert("Supplier login");

            else
            alert("supplier login fail");

        }
    }
</script>
</head>
<body>
<div class="container">
<div class="main">
<h2>Login Form</h2>
<form id="form_id" method="post" name="myform">
<label>User Name :</label>
<input type="text" placeholder="Enter username" name="username" id="username"/>
<label>Password :</label>
<input type="password" placeholder="Enter Password" name="password" id="password"/>
<input type="button" value="Login" id="submit" onclick="validate()"/>
</form>
</body>
</html>