Question:You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5.
You create a login Web form by using the following code fragment:
<asp:ScriptManager ID="ScriptManager1" runat="server" />
<asp:TextBox runat="server" ID="txtUser" Width="200px" />
<asp:TextBox runat="server" ID="txtPassword" Width="200px" />
<asp:Button runat="server" ID="btnLogin" Text="Login"
OnClientClick="login(); return false;" />
When a user clicks the btnLogin Button control, the login() client-side script is called to authenticate the user. The
credentials provided in the TextBox controls are used to call the client-side script.
You also add the following client-script code fragment in the Web form:
01 <script type="text/javascript">
02 function login() {
03 var username = $get('txtUser').value;
04 var password = $get('txtPassword').value;
05
06 â–º // authentication logic.
07 }
08 function onLoginCompleted(validCredentials, userContext,
09 methodName)
10 {
11 // notify user on authentication result.
12 }
13
14 function onLoginFailed(error, userContext, methodName)
15 {
16 // notify user on authentication exception.
17 }
18 </script>
The ASP.NET application is configured to use Forms Authentication. The ASP.NET AJAX authentication service is
activated in the Web.config file.
You need to ensure that the following workflow is maintained:
on successful authentication, the onLoginCompleted client-script function is called to notify the user.
on failure of authentication, the onLoginFailed client-script function is called to display an error message.
Which code segment should you insert at line 06?
A var auth = Sys.Services.AuthenticationService;
auth.login(username, password, false, null, null,
onLoginCompleted, onLoginFailed, null);B var auth = Sys.Services.AuthenticationService;
auth.set_defaultFailedCallback(onLoginFailed);
var validCredentials = auth.login(username, password, false,
null, null, null, null, null);
if (validCredentials)
onLoginCompleted(true, null, null);
else
onLoginCompleted(false, null, null);C var auth = Sys.Services.AuthenticationService;
auth.set_defaultLoginCompletedCallback(onLoginCompleted);
try {
auth.login(username, password, false, null, null, null, null, null);
} catch (err) {
onLoginFailed(err, null, null);
}D var auth = Sys.Services.AuthenticationService;
try {
var validCredentials = auth.login(username, password, false,
null, null, null, null, null);
if (validCredentials)
onLoginCompleted(true, null, null);
else
onLoginCompleted(false, null, null);
} catch (err) {
onLoginFailed(err, null, null);
}
+ AnswerA
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