CGI類方法：

這裡是一個CGI類方法列表：

SN	說明方法
1	CGI::new([ level="query"]) Creates a CGI object. level may be one of the following options. If one of the HTML levels is specified, the following methods are defined for generating output conforming to that level: query: No HTML output generated html3: HTML3.2 html4: HTML4.0 Strict html4Tr: HTML4.0 Transitional html4Fr: HTML4.0 Frameset
2	CGI::escape( str) Escapes an unsafe string using URL-encoding.
3	CGI::unescape( str) Expands a string that has been escaped using URL-encoding.
4	CGI::escapeHTML( str) Escapes HTML special characters, including: & < >.
5	CGI::unescapeHTML( str) Expands escaped HTML special characters, including: & < >.
6	CGI::escapeElement( str[, element...]) Escapes HTML special characters in the specified HTML elements.
7	CGI::unescapeElement( str, element[, element...]) Expands escaped HTML special characters in the specified HTML elements.
8	CGI::parse( query) Parses the query and returns a hash containing its key-value pairs.
9	CGI::pretty( string[, leader=" "]) Returns a neatly formatted version of the HTML string. If leader is specified, it's written at the beginning of each line. The default value for leader is two spaces.
10	CGI::rfc1123_date( time) Formats the data and time according to RFC-1123 (for example, Tue, 2 Jun 2008 00:00:00 GMT).

CGI實例方法：

假設c是由 CGI::new 創建的實例。現在，這裡是一個列表的方法可以應用到這個實例：

SN	說明方法
1	c[ name] Returns an array containing the value of the field name corresponding to name.
2	c.checkbox( name[, value[, check=false]]) c.checkbox( options) Returns an HTML string defining a checkbox field. Tag attributes may be specified in a hash passed as an argument.
3	c.checkbox_group( name, value...) c.checkbox_group( options) Returns an HTML string defining a checkbox group. Tag attributes may be specified in a hash passed as an argument.
4	c.file_field( name[, size=20[, max]]) c.file_field( options) Returns an HTML string defining a file field.
5	c.form([ method="post"[, url]]) { ...} c.form( options) Returns an HTML string defining a form. If a block is specified, the string produced by its output creates the contents of the form. Tag attributes may be specified in a hash passed as an argument.
6	c.cookies Returns a hash containing a CGI::Cookie object containing keys and values from a cookie.
7	c.header([ header]) Returns a CGI header containing the information in header. If header is a hash, its key-value pairs are used to create the header.
8	c.hidden( name[, value]) c.hidden( options) Returns an HTML string defining a HIDDEN field. Tag attributes may be specified in a hash passed as an argument.
9	c.image_button( url[, name[, alt]]) c.image_button( options) Returns an HTML string defining an image button. Tag attributes may be specified in a hash passed as an argument.
10	c.keys Returns an array containing the field names from the form.
11	c.key?( name) c.has_key?( name) c.include?( name) Returns true if the form contains the specified field name.
12	c.multipart_form([ url[, encode]]) { ...} c.multipart_form( options) { ...} Returns an HTML string defining a multipart form. If a block is specified, the string produced by its output creates the contents of the form. Tag attributes may be specified in a hash passed as an argument.
13	c.out([ header]) { ...} Generates HTML output. Uses the string produced by the block's output to create the body of the page.
14	c.params Returns a hash containing field names and values from the form.
15	c.params= hash Sets field names and values in the form using a hash.
16	c.password_field( name[, value[, size=40[, max]]]) c.password_field( options) Returns an HTML string defining a password field. Tag attributes may be specified in a hash passed as an argument.
17	c.popup_menu( name, value...) c.popup_menu( options) c.scrolling_list( name, value...) c.scrolling_list( options) Returns an HTML string defining a pop-up menu. Tag attributes may be specified in a hash passed as an argument.
18	c.radio_button( name[, value[, checked=false]]) c.radio_button( options) Returns an HTML string defining a radio button. Tag attributes may be specified in a hash passed as an argument.
19	c.radio_group( name, value...) c.radio_group( options) Returns an HTML string defining a radio button group. Tag attributes may be specified in a hash passed as an argument.
20	c.reset( name[, value]) c.reset( options) Returns an HTML string defining a reset button. Tag attributes may be specified in a hash passed as an argument.
21	c.text_field( name[, value[, size=40[, max]]]) c.text_field( options) Returns an HTML string defining a text field. Tag attributes may be specified in a hash passed as an argument.
22	c.textarea( name[, cols=70[, rows=10]]) { ...} c.textarea( options) { ...} Returns an HTML string defining a text area. If a block is specified, the string produced by its output creates the contents of the text area. Tag attributes may be specified in a hash passed as an argument.

HTML生成方法：

可以創建任何HTML標簽，通過使用相應的HTML標記名具有任何CGI實例。例如：

#!/usr/bin/ruby

require "cgi"
cgi = CGI.new("html4")
cgi.out{
   cgi.html{
      cgi.head{ "
"+cgi.title{"This Is a Test"} } +
      cgi.body{ "
"+
         cgi.form{"
"+
            cgi.hr +
            cgi.h1 { "A Form: " } + "
"+
            cgi.textarea("get_text") +"
"+
            cgi.br +
            cgi.submit
         }
      }
   }
}

CGI對象屬性：

可以訪問任何使用CGI實例以下屬性：

屬性	返回值
accept	Acceptable MIME type
accept_charset	Acceptable character set
accept_encoding	Acceptable encoding
accept_language	Acceptable language
auth_type	Authentication type
raw_cookie	Cookie data (raw string)
content_length	Content length
content_type	Content type
From	Client email address
gateway_interface	CGI version string
path_info	Extra path
path_translated	Converted extra path
Query_string	Query string
referer	Previously accessed URL
remote_addr	Client host address
remote_host	Client hostname
remote_ident	Client name
remote_user	Authenticated user
request_method	Request method (GET, POST, etc.)
script_name	Program name
server_name	Server name
server_port	Server port
server_protocol	Server protocol
server_software	Server software
user_agent	User agent