Introduction to ColdFusion Markup Language - Tags Used in CFML

Let's look at some of the tags that make up CFML. This section provides a quick overview of some of the most common tags and their use. This should give you a general idea of what ColdFusion MX 6.1 is capable of. Following later are descriptions and code snippets detailing how to use some of these tags in a ColdFusion page.

ColdFusion MX 6.1 has more than 100 CFML tags, which Macromedia's documentation breaks down into the following categories:

• Application framework
  
• Database manipulation
  
• Data output
  
• Debugging
  
• Exception handling
  
• Extensibility
  
• File management
  
• Flow-control
  
• Forms
  
• Internet protocol
  
• Page processing
  
• Variable manipulation

However, what's more important are the specific tags that you will discover you use every day in ColdFusion. Some of the more useful tags are:

1. <cfchart>: Generates charts on the fly in a variety of formats, including.jpeg,.png, and.swf(Flash).
   
2. <cfdirectory>: Performs directory management tasks and allows you to create, delete, rename, or list the contents of a directory.
   
3. <cfdump>: Displays the contents of a variable to the screen for debugging purposes. Variables can contain simple values such as strings and numbers, or complex data such as Recordsets and structures.
   
4. <cferror>: Tells ColdFusion how to handle errors that occur in your application.
   
5. <cffile>: Performs file-management tasks and allows you to read, write, delete, move, rename, or append data to files on the server.
   
6. <cfform>: Similar to HTML forms, except that it allows developers to take advantage of automatically generated JavaScript validation provided by the ColdFusion server.
   
7. <cfftp>: Allows ColdFusion to FTP files to and from remote FTP sites.
   
8. <cffunction>: Allows you to write your own custom functions using CFML tags.
   
9. <cfhttp>: Allows you to post variables to remote sites, or grab the contents of a file on a different server.
   
10. <cfif>: Performsif ... then ... elselogic in ColdFusion, running code only if certain conditions are met.
    
11. <cfinclude>: Embeds other HTML or CFML code into the current document. This allows developers to break up larger files and reuse certain code/functions throughout the site.
    
12. <cfinput>: Used in conjunction with the<cfform>tag to take advantage of built-in JavaScript validation.
    
13. <cflocation>: Redirects the currently running page to a different page, or redirects users to a different site altogether.
    
14. <cfloop>: Allows you to loop over Recordsets and structures a defined number of times, or while a certain condition is true.
    
15. <cfmail>: Sends an e-mail to a single user or group of users.
    
16. <cfmodule>: Allows you to call your own custom tags with ColdFusion.
    
17. <cfoutput>: Used to output the value of a variable, or loop over a Recordset.
    
18. <cfparam>: Checks to see if a certain variable exists; if not, it creates the variable and assigns a default value. It can also be used to validate the data type of a variable.
    
19. <cfquery>: Used to pass SQL statements to a database.
    
20. <cfqueryparam>: Used within<cfquery>to insert dynamic values into a SQL statement.
    
21. <cfset>: Define the value of a variable.
    
22. <cfstoredproc>: Execute a stored procedure (if supported by your database of choice).
    
23. <cfswitch>: Passes control to a matching<cfcase>tag and evaluates passed expressions. This could be performed using a series of<cfif>tags, but this method saves space and simplifies things.
    
24. <cftry>: Monitors a block of ColdFusion code and tries to catch any errors that may occur. It is used in conjunction with the<cfcatch>tag.

ColdFusion also has a couple of special files that are triggered before or after every user request and can be used to hold site-wide variables or settings; we will look at these now.

Next: The Application.cfm File >>
 

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