Submit form does not work correctly - php

Question

<div class="container">
<form class="form-signin">
<h2 class="form-signin-heading">Please sign in</h2>
<?php echo form_open('login/validate_credentials');?>
<?php $u = 'placeholder="Username"';
$p = 'placeholder="Password"';?>
<?php echo form_input('username','',$u,'class="input-block-level"');?>
<?php echo form_password('password','',$p,'class="input-block-level"');?>
<label class="checkbox">
<input type="checkbox" value="remember-me"> Remember me
</label>
<?php echo form_submit('submit','Sign in','class= "btn btn-primary"');?>
<?php echo anchor('login/signup','Sign up!', 'class= "btn btn-primary"');?>.<br/><br />
<?php echo anchor('login/admin_log','Go to admin login page');?>
<?php echo form_close();?>
</form>
</div>
I have a login form. When I click sign , it's not redirecting me to the form_open page.

Answer 1

you need to create an action for the form, usually a php script on a different page to handle the data:
as an example:
<form action= "../create_comment.php" method="post" name="comments_form" id="comment" enctype="multipart/form-data">
<div>
<label>Name<span>*</span></label>
<input name="name" type="text" value=" ">
</div>
</form>

Answer 2

You have two forms Parent and child(form inside form).
Submitting the form will process parent form. Simply remove the first (parent) <form> tag.
<form class="form-signin">
^^^^^^^^^^^^^^^^^^^^^^^^^^ ------ remove this
...
...
</form>
^^^^^^^ ------ and this

Answer 3

It looks like you might be using CodeIgniter?
You have 2 form tags in your code.
here: <form class="form-signin">...</form>
and here:
<?php echo form_open('login/validate_credentials');?>...<?php echo form_close();?>
Get rid of this one: <form class="form-signin">...</form>
Your second form tag will handle everything for you. The output will look something like this:
<form method="post" accept-charset="utf-8" action="http:/example.com/index.php/login/validate_credentials" />
If you need to add a class or any other property to the form tag, do this:
$attributes = array('class' => 'email', 'id' => 'myform');
echo form_open('email/send', $attributes);
Form helper on CI Docs