Forms : different types of input

password : a single line of text which is not echoed on the screen

hidden: an element which the user never sees, but which is passed back to the server

Handy to use the same script in different contexts : the hidden value is then the parameter of the script. Could be used to simulate sessions also.

<input type="password" name="passwd"
     size="30" maxlength="50">
<input type="hidden" name="param"
     value="black">