eXtropia: the open web technology company
Technology | Support | Tutorials | Development | About Us | Users | Contact Us
 ::   Tutorials
 ::   Presentations
Perl & CGI tutorials
 ::   Intro to Perl/CGI and HTML Forms
 ::   Intro to Windows Perl
 ::   Intro to Perl 5
 ::   Intro to Perl
 ::   Intro to Perl Taint mode
 ::   Sherlock Holmes and the Case of the Broken CGI Script
 ::   Writing COM Components in Perl

Java tutorials
 ::   Intro to Java
 ::   Cross Browser Java

Misc technical tutorials
 ::   Intro to The Web Application Development Environment
 ::   Introduction to XML
 ::   Intro to Web Design
 ::   Intro to Web Security
 ::   Databases for Web Developers
 ::   UNIX for Web Developers
 ::   Intro to Adobe Photoshop
 ::   Web Programming 101
 ::   Introduction to Microsoft DNA

Misc non-technical tutorials
 ::   Misc Technopreneurship Docs
 ::   What is a Webmaster?
 ::   What is the open source business model?
 ::   Technical writing
 ::   Small and mid-sized businesses on the Web

Offsite tutorials
 ::   ISAPI Perl Primer
 ::   Serving up web server basics
 ::   Introduction to Java (Parts 1 and 2) in Slovak


introduction to web programming
handling image input  
As you saw earlier, it is very easy to use the NAME value of an HTML SUBMIT button to determine which action to perform in a script. Thus, we typically see code as follows:

if (delete button ne "")
  do something

In other words, if the user has clicked the delete button (and the delete button has been assigned the VALUE), we will perform a deletion. If however, some other button is pressed, the VALUE of the delete button will be null and the action will not be performed.

However, what if the user clicked an INPUT TYPE = "image" button?

In this case, we will use similar logic...

if ($form_data{'delete_image.y'} > 0)
  do something

As you can see, the script checks to see if the y coordinate has been assigned a value (meaning the user clicked on it) and if so, performs an action.

Previous | Next | Table of Contents