I have a password element which I use for signing in process. But, I get this weird username and password once the page gets opened !!

but the problem is when I don't user password element but only input I don't get this weird username and password, what should I do to make them blank?
Here's the code
echo"
<center><small>
<br />
<p> Welcome Guest you can sign in here:</p></br>
<form action = \"HomeWork.php\" method = \"post\">
User name*: <input type=\"text\" name=\"Username\" />
Password*: <input type=\"password\" name=\"Password\" />
<a href=\"Signup.php\">or Sign up !</a>
<br /> <br />
<input type=submit value=Submit align=\"middle\" />
</form>
</small></center>";
Can you help me??
AutoCompletecache. If you're using Firefox, look atPreferences > Security > Saved Passwords. Also, you can save yourself the headache of escaping your double-quotes by using single-quotes with yourecho.