Getting Information through HTML Forms

webDeV@rgu
getting information from users
html forms
quick tip…
THE “SECURITY HACK” AT THE END OFTHIS PRESENTATION IS SOMETHINGTHAT EVERYONE SHOULD KNOW!

• HTML Forms
• Form Presentation
• Form Elements
• Input Types
• Input Attributes
• Form Security
Overview

• Capturing user input
• registering user information
• entering username and password for login
• posting status updates to social networks
• submitting a search query
• taking a questionnaire
• Transmitting user input elsewhere
• send to client side JavaScript for validation
• send to server side process (PHP, Java,
JavaScript)
Purpose of html Forms

• The form tag contains all the input elements
• <form> … </form>
• Input elements can be of <input type=“” />
• Text/password/file or textarea
• Radio button or Checkbox
• Select boxes
• All input elements should be given a form label
• Improves accessibility if using a screen reader
• <label> … </label>
• Fieldsets can be used to graphically group input
elements together
• <fieldset> … </fieldset>
Basic form elements

<form>
<ﬁeldset>
<legend>Please leave a comment...</legend>
<label for="name">Name:</label>
<input type="text" name="name" value="" />
<label for="email">Email:</label>
<input type="text" name="email" value="" />
<label for="comments">Comment:</label>
<textarea name="comments" cols="45“ rows="5">
</textarea>
<input type="submit" value="Submit" />
</ﬁeldset>
</form>

• Best practice is to use CSS
• However, tables are still used a lot for layout of
form elements
• better than a messy form
Form Presentation

<form>
<ﬁeldset>
<label for="name">Name:</label>
<input type="text" name="name" value="" />
<br>
<label for="email">Email:</label>
<input type="text" name="email" value="" />
<br>
<label for="comments">Comment:</label>
<textarea name="comments" cols="45" rows="5"></textarea>
<br>
<input type="submit" value="Submit" />
</ﬁeldset>
</form>

Column 1 Column 2
Row 1
Row 2
Row 3
Row 4

Form Presentation
• Best practice is to use CSS
• However, tables are still used a lot for layout of
form elements
• better than a messy form
• Next week we will look at CSS in a lot more detail
so that you can get the hang of it.

• Provides simple text input
text
<form>
<label for=“ﬁrstname>First name:</label><br>
<input type="text" name="ﬁrstname"><br>
Last name:<br>
<input type="text" name="lastname">
</form>

• Provides text input that is hidden from the user
password
<form>
User name:<br>
<input type="text" name="username"><br>
User password:<br>
<input type="password" name="psw">
</form>

<form action="action_page.php">
First name:<br>
<input type="text" name="ﬁrstname" value="Mike"><br>
Last name:<br>
<input type="text" name="lastname" value="Crabb"><br><br>
<input type="submit" value="Submit">
</form>
• Submit button for forms
submit

<form>
Birthday:
<input type="date" name="bday">
</form>
• The <input type="date"> is used for input ﬁelds that
should contain a date.
date

• Provides for a selection of zero or more items from
a list of options
checkboxes
<input type="checkbox" name="pets" value="loveCats">I love cats <br> 
<input type="checkbox" name="pets" value="loveDogs">I love dogs

• Provides for only one selection from a list of options
Radio buttons
<input type="radio" name="cats" value="loveCats">I love cats <br> 
<input type="radio" name="cats" value="hateCats">I have no soul

• Choose from a list of options
• use the <select> tag
• list <options>
Selection (drop down) Box
<label for="degreeTitle">Degree Title:</label> 
<select name="degreeTitle"> 
<option value="cs">Computer Science</option> 
<option value="dm">Digital Media</option> 
<option value="cnmd">Computer Network Management and Design</option
</select>

coloUr
<form>
Select your favorite color:
<input type="color" name="favcolor">
</form>

email
<form>
E-mail:
<input type="email" name="email">
<input type="submit">
</form>

URL
<form>
Add your homepage:
<input type="url" name="homepage">
</form>

HTML5 form improvements
email
url
Reset
color
check input is valid email address
(something@something.something)
check input is valid web address
(http://www.something.something)
Clears everything on the page
Select a colour
american spelling

Form
elements
input attributes

• The value attribute specifies the initial value for an
input field:
value
<form action="">
First name:<br>
<input type="text" name="firstname" value="John">
<br>
Last name:<br>
</form>

• The readonly attribute specifies that the input field
is read only (cannot be changed)
read only
<form action="">
First name:<br>
<input type="text" name="firstname" value="John" readonly>
<br>
Last name:<br>
</form>

• The disabled attribute specifies that the input field
is disabled.
• A disabled element is un-usable and un-clickable.
• Disabled elements will not be submitted
Disabled
<form action="">
First name:<br>
<input type="text" name="firstname" value="John" disabled>
<br>
Last name:<br>
</form>

• The size attribute specifies the size (in characters)
for the input field
size
<form action="">
First name:<br>
<input type="text" name="firstname" value="John" size="40">
<br>
Last name:<br>
</form>

• The maxlength attribute specifies the maximum
allowed length for the input field:
maxlength
<form action="">
First name:<br>
<input type="text" name="firstname" maxlength="10">
<br>
Last name:<br>
</form>

• The autocomplete attribute specifies whether a
form or input field should have autocomplete on or
off
autocomplete
<form autocomplete="on">
First name:<input type="text" name="fname"><br>
Last name: <input type="text" name="lname"><br>
E-mail: <input type="email" name="email"
autocomplete="off"><br>
<input type="submit">
</form>

placeholder
• The placeholder attribute speciﬁes a hint that
describes the expected value of an input ﬁeld (a
sample value or a short description of the format).
<input type="text" name="fname" placeholder="First name">

required
• When present, it specifies that an input field must
be filled out before submitting the form.
• The required attribute works with the following
input types: text, search, url, tel, email, password,
date pickers, number, checkbox, radio, and file.
Username: <input type="text" name="username" required>
This one is
important

form security
• Forms can be quite insecure when we are using
them, we need to make sure that the right data
is being seen by the right people
• and that no-one can get access to the
really sensitive data!
For example…here’s how to ﬁnd our a password on
an unsecured computer
PS - DON’T DO THIS ONE SOMEONE ELSES
COMPUTER - YOU’ll GET INTO A LOT OF TROUBLE!!

I’ve visited a website and have put in my
username and password into the box
provided. Let’s say that now I have to step
away from my computer for 5 seconds…

Some unsavoury character comes along
and looks at my screen. They right click on
the password field and then go to inspect, I
wonder what they are up to?

Now they are looking at the HTML for this
web page and have an interest in the field
that my password is in. It’s ok…its secure
(it really isn’t).

They change the form element from:
<input type=“Password”>
to
<Input Type=“text”>
and now my password is being shown to the
world #awkward!

• HTML Forms
• Form Presentation
• Form Elements
• Input Types
• Input Attributes
• Form Security
Recap

get in touch!
@mike_crabb
Lecturer in Web Development at Robert Gordon University
(Scotland)
@rgucomputing
Robert Gordon University - School of Computing Science and
Digital Media

Getting Information through HTML Forms

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Getting Information through HTML Forms