Background:

Creating forms with HTML is simple! You can use the <input> tag in conjunction with the attributes "text" for textbox, "radio" for round radio buttons, and "checkbox" for square checkboxes to allow the user to enter in information. The attribute "submit" is used to submit the form (to email or to a script for further processing) and "reset" is used to clear the form.

Javascript functions called "methods" in object oriented programming) can be used to check the form for errors. While completely "bullet-proofing" the information entered by the user is a difficult task, one can check for simple errors rather easily. The Javascript can be executed when the submit button is clicked by means of the <form> tag with the attribute: "onSubmit".

Specifications:

You will create a form that allows the user to enter a subscription for an imaginary newspaper. Click here for a sample of what your page should look like.

Your Javascript will check:

• that the user has subscribed to at least one paper
• that the user has entered something each of the last name, first name, and address fields
• the user has entered selected either to supply an email address or a phone number. If the user enters email, the address should contain a '@' and a '.', otherwise an error message is issued.

Preparation:

Getting Started:

• You need to be sure you are in your public_html directory.
  login to your account (if you are not logged in) and type:
  >cd public_html
  Then to verify that this worked type:
  >pwd

• As with the last assignment, you will need to use a unix editor to create the web page. You may use any editor, but pico is the easiest. (It has an interface like pine, if you have used pine for email.) Click here for basic pico commands
• You may want to copy and paste the Javascript from form.html to help prevent making mistakes. In the browser, when you are viewing the Page Source, select all the code and then type Ctrl-c (copy). Then go back to pico and paste the code into your new document.
• Important! Before testing your form, be sure to change the email address after "mailto:" to your email address.

Remember these programming rules:

• Functions (or "methods") start with the word "function" followed by a function name and parentheses that may contain a value that is being sent to the function (an "argument").
• Functions begin with { and end with }
• conditional statements are in the format:
  if (condition)
  {
  //statements go here
  }
• Statements you want Javascript to ignore (comments) begin with //
• You will need to use the logical operators:
  • && (AND)
  • || (OR)
  • ! (NOT)

If you get a Javascript error, or if it just doesn't work. Read back over what you have written carefully. A single missing quote or typo can prevent it from working. Remember that case matters!

Using the the function that checks for a valid email address as a model, see if you can write a function that checks for a valid phone number.