Dropdown menu dissapears after clicking on it

I have a form in the drop down and I can’t edit the fields without it dissapearing after clicking. Here is the code

						<a data-toggle="dropdown" href="ace/#" class="dropdown-toggle" >
								<img class="nav-user-photo" src="ace/assets/avatars/user.jpg" alt="Jason's Photo" />
								<span class="user-info">
								<?php if ($user=="") {echo"<small>Register!,</small>Guest!";}else{echo"<small>Welcome,</small>User!";}?>

								<i class="icon-caret-down"></i>

						<?php if ($user_id == "") {?>
						            <div class="dropdown-menu"  style="padding: 15px; padding-bottom: 0px;">
                <form action="index.php" method="post">
                    Username:<br />
                    <input type="text" name="username" class="dropdown" value="<?php echo $submitted_username; ?>" />
                    <br />
                    Password:<br />
                    <input type="password" name="password" class="dropdown" value="" />
                    <br />
                    <input type="submit" class="btn btn-info" value="Login" />
      <script type="text/javascript">
$('.dropdown-menu input').click(function(event){

Sorry, it might be the Holiday, but I can’t see anything obvious. Got a link to an online page with the problem?

this is the page:http://collegeexchange.org/budget/index.php

it happens when you click the register link, a pop up shows up, but when you click the input field, it disappears.

I get a bunch of

Warning: Empty string passed to getElementById().
Source File: http://ajax.googleapis.com/ajax/libs/jquery/2.0.3/jquery.min.js
Line: 4

Code being minified and me being tired isn’t very helpful, but Im wondering if

$('.dropdown-menu input').click(function(event){

might be going to the ul’s that have that class but no input tags and hence causing empty strings?

If you look at the page in your browser’s dev tools, I see:

Uncaught ReferenceError: $ is not defined index.php:282
Uncaught TypeError: Cannot call method 'replace' of undefined jquery.flot.min.js:28

The first error means that you are trying to use the jQuery syntax before including the library.

I’d try fixing both those errors and seeing if that helps.

If not, could you make a bare bones example that demonstrates your problem.
Your current page contains over 1,200 lines of code.
Try to reduce that to about 50 - 100.

haha it was executing before jquery was loaded. Thank you :).