I don't understand why it wouldn't work.
TextEdit is just a simple text editor like most others. And as long as you save the file with a ".htm" or ".html" extension, you should be fine.
Here, try copying/pasting this into a new document in TextEdit, and saving it as "form.htm".
Here's one. Just save it to your hard drive with an extension of ".htm" or ".html", and open it in your favorite browser.
<html>
<head>
<title>My signup</title>
<style type="text/css">
body { margin: 0; padding: 0; }
form { font-family: Verdana, Helvetica, sans-serif; font-size: 20px; }
.labels { width: 125px; float: left; background-color: #F8ECE0; padding-top: 2px; padding-bottom: 2px; }
.inputs { width: 200px; margin-left: 0; padding-top: 4px; padding-bottom: 3px; float: left; font-family: Verdana; background-color: #F8ECE0; }
form input { border: 1px solid gray; background-color: #fff; }
form button { margin-left: 66%; margin-right: 66%; }
form br { background-color: #fff; clear: both; }
</style>
</head>
<body>
<!-- myscript.php is a script that inserts the username/password into a table -->
<form action="myscript.php">
<div class="labels"><label for="username">Username:</label></div> <div class="inputs"><input type="text" name="username"></div><br>
<div class="labels"><label for="email_addr">Email:</label></div> <div class="inputs"><input type="text" name="email_addr"></div><br>
<div class="labels"><label for="password">Password:</label></div> <div class="inputs"><input type="password" name="passwd"></div><br>
<div class="inputs"><button name="submit" value="Submit">Submit</button></div><br>
</form>
<br>
© 2008 by Me
</body>
</html>
