The problem to make the submit button inside the content section to align in right or left

The problem to make the submit button inside the content section to align in right or left

I have a problem in using the CSS class ="ui-btn- left or right". It works fine in header and footer
like:
<div data-role="header">
            <a  href="#" data-role="button" data-inline="true" class="ui-btn-right">Contacts</a>
            <input type="submit" name="loginSubmit" id="loginSubmit" value="Login" data-inline="true" class="ui-btn-right" />
            </div>

But when I applied in content or the form in content, it is not workiing at all. Like:
<div data-role="content">
             <a href="#" data-role="button" data-inline="true" class="ui-btn-right" >anchor tag</a>
                <form id="login" name="login" action="login.php" method="POST">
                    <label for="username">Username: </label>
                    <input type="text" name="username" id="username" value="" /><br />
                    <label for="password">Password:</label>
                    <input type="password" name="password" id="password" value="" /><br />
                    <input type="hidden" name="hiddenInput" id="hiddenInput" value="secret message" />
                 
                    <input type="submit" name="loginSubmit" id="loginSubmit" value="Login" data-inline="true" class="ui-btn-right" />
                    <!--the "ui-btn-right" class is not working in the content section( in a or input tag, but work both in footer and header-->
                 
                  
                </form>
            </div>