WWW Forms and Search

Forms URL - always fetch a particular page What if the information we want varies from time to time and from user to user?

Forms

Forms - requests to a web-site How to get information from the user When to send the request Where to send the request How to send the user’s information with the request

Example form First name Last name

Labels Example form First name Last name

Labels

How to get info from the user Example form First name Last name

Parts to an input tag Name - the name that this input information will be given Size - the number of characters that the user can type

When to send the request Example form First name Last name

When to send the request

Where to send the request Example form First name Last name

How to send the user information in a URL Example form First name Last name

How to send the user information in a URL Example form First name Last name

How to send the user information in a URL Example form First name Last name

Forms - How does the server respond? Not every URL refers to a page CGI - Common Gateway Interface You can give a server a program and place it at a URL. The server will then run the program and return its result rather than fetch a page

Search How do we describe the page that we want?

Search How does Google know where that page is? Find as many web pages as you can For each web page prepare a list of words on that page For each word in all of the web keep a list of pages that have that word

How does your browser ask for the search

CS Which page?

CS the winner Why? Both have the words CS 100 CS 100 in CS 100 in text

Problems with word searches Search for “doctor” What about pages with the word “doctors”? What about pages with the word “physicians”? What about pages about “witch doctors”? What if the page only has a picture of a doctor? What if the only use of the word doctor is in a picture?

Blocking pornography The reverse of the search problem I don’t want pages that have this –How do you describe what you don’t want?

Blocking pornography Keep a list of all bad sites –If site is on the black list then refuse to make an Internet connection –What if someone creates a new site? Keep a list of bad words and block any URL or page that has those words –What about “Middlesex, England”? –What about “breast cancer”? –What about slang words? –What about pictures?