Tuesday, December 21, 2010

9:42 PM
2
In this example, first of all we’ll validate the user login detail from ajax showing the messages with some animation. If authenticated, the user will be redirected to the secure page “secure.php”. If you’ll try to directly access “secure.php”, you can’t do that.


Now let’s look at the code how to do this,

HTML Code

< form method="post" action="" id="login_form" />
  < input name="username" type="text" id="username" value="" maxlength="20" />
  < input name="password" type="password" id="password" value="" maxlength="20" />
  < input name="Submit" type="submit" id="submit" value="Login" />
< /form >

As you can see in html code, we’ve created the form with id “login_form”.
And furthermore, the CSS code is same as the one available in the pervious post of checking user availability in ajax and php.

JavaScript Code for Ajax Login validation system in PHP


First of all we need to use the jQuery library in our code,

< script src="jquery.js" type="text/javascript" language="javascript"></script >

Now let’s look at the code in javaScript to call ajax and show the animated message with fading effects.

$("#login_form").submit(function()
{
        //remove all the class add the messagebox classes and start fading
        $("#msgbox").removeClass().addClass('messagebox').text('Validating....').fadeIn(1000);
        //check the username exists or not from ajax
        $.post("ajax_login.php",{ user_name:$('#username').val(),password:$('#password').val(),rand:Math.random() } ,function(data)
        {
          if(data=='yes') //if correct login detail
          {
                $("#msgbox").fadeTo(200,0.1,function()  //start fading the messagebox
                {
                  //add message and change the class of the box and start fading
                  $(this).html('Logging in.....').addClass('messageboxok').fadeTo(900,1,
                  function()
                  {
                     //redirect to secure page
                     document.location='secure.php';
                  });
                });
          }
          else
          {
                $("#msgbox").fadeTo(200,0.1,function() //start fading the messagebox
                {
                  //add message and change the class of the box and start fading
                  $(this).html('Your login detail sucks...').addClass('messageboxerror').fadeTo(900,1);
                });
          }
       });
       return false;//not to post the  form physically
});


in above code, where the user is validated, he’ll be logged into the “secure.php” using “document.location” in JavaScript.

$("#password").blur(function()
{
        $("#login_form").trigger('submit');
});

Well, as you can see above javaScript’s code, when focus is moved away from the password it also call the for sumit action. Basically whenever you hit tab button in password field, it starts validating the user detail using ajax.

PHP Code for Ajax Login validation system


First of all lets’s look at the code of the “ajax_login.php”.

//get the posted values
$user_name=htmlspecialchars($_POST['user_name'],ENT_QUOTES);
$pass=md5($_POST['password']); 

//now validating the username and password
$sql="SELECT user_name, password FROM tbl_user WHERE user_name='".$user_name."'";
$result=mysql_query($sql);
$row=mysql_fetch_array($result); 

//if username exists
if(mysql_num_rows($result)>0)
{
        //compare the password
        if(strcmp($row['password'],$pass)==0)
        {
                echo "yes";
                //now set the session from here if needed
                $_SESSION['u_name']=$user_name;
        }
        else
                echo "no";
}
else
        echo "no"; //Invalid Login

As you can see above, the user login detial is validated from the database. If the user login detail doesn’t exists, it just returns the “no” values and if the user login detial does exists the it just return “yes” values with setting username in session variable.
Finally, let’s look at the code of secure.php

if(empty($_SESSION['u_name']))
  header("Location:index.html");
//if logout then destroy the session and redirect the user
if(isset($_GET['logout']))
{
  session_destroy();
  header("Location:index.html");
}
echo " <a href='secure.php?logout'><b>Logout<b></a> ";
echo " <div align='center'>You Are inside secured Page</a> ";

As you can see above the code of “secure.php” is simpleforward. If the user is not authenticated by session then he’ll be redirected to “index.html”. And there is link for “logout” in this page form where user can destroy the seession.


Implementation Guide:

To implement this code, dump the tbl_user “table” available in the zip file to your database and configure the database connection in “ajax_login.php.



2 comments:

Muhammad Azeem said...

This is a nice article..
Its very easy to understand ..
And this article is using to learn something about it..

c#, dot.net, php tutorial

Thanks a lot..!

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