HTML Forms Elements (highly abridged)

Name Typical usage HTML Notes
Form (nothing visual) 
<form method="GET" action="GetAnswer.py">
 If the file named in the action attribute has no path, then it must be in the same directory as the file that contains this HTML <form> tag.
one-line text box

City: 

<input type="text" name="city" size="20" value="Brooklyn">
 If there's no value attribute, there'll be no default text (e.g. "Brooklyn") inside the input box when it appears to the user.
checkbox Are you alive?   
<input type="checkbox" name="Is-Alive" value="Yup">
 If the user does not check this checkbox, no data about this checkbox will be sent to the web server.  If the user does check it, then
Is-Alive=Yup
will be sent.
drop-down menu Planet: 
<select name="planet" size="1">
  <option>Venus</option>
  <option>Earth</option>
  <option selected>Mars</option>
  <option>Pluto!</option>
</select>
 If the user selects, say, "Venus", then
planet=Venus
will be sent to the server.
radio buttons Alive   Dead   Zombie 
<input type="radio" name="life_state" value="alive">
<input type="radio" name="life_state" value="dead">
<input type="radio" name="life_state" value="undead" checked>
 Only one member of the "life_state" radio button group will be selected by the user, and that value will be sent to the web server.  In this case:
life_state=undead
will be sent.
scrolling text box Tweet: 
<textarea rows="3" name="a_tweet" cols="20">
Meaningless chatter...
</textarea>
 Can contain lots of text...
Submit button   
<input type="submit" name="fred" value="I'm done.">
 Pressing this button triggers the browser to send the values of all the elements in this group (all the elements enclosed by the <form> tag) to the web server.

Note: There are lots of options (attributes) to many of the form controls above that we haven't mentioned.  For instance, you can allow more than one drop-down menu option to be selected by the user at a time (the user can, for instance, select 3 of them simultaneously).  There is much on the Web about some of the attributes not covered here.  Here's one reference place that's pretty good (although not complete).