It's very simple to run a script (for example, a CGI script) by clicking a button in a form:
(Note: For display purposes, the code snippets in this article use square brackets '[' instead of angle brackets. You will need to change these to angle brackets in order to use the code.)
[form name="form1" method="post" action="/cgi-bin/updatePage.cgi"]
:
:
[/form]
Sometimes, however, you might need to run a script automatically from within a web page without requiring the user to perform an action. You might want to do this if, for example, you have one or more variables that have been generated perhaps by another script, which you need to process without user interaction.
If you insert the following code into an HTML page, the script (in our case, updatePage.cgi) will be automatically executed when the web page is loaded into a browser.
[img src="/cgi-bin/updatePage.cgi" height="1" width="1"]
In order to ensure that a broken link is not generated by the cgi script itself, include the following code in the cgi script itself.
print "Content-type: image/gif";
open IN, 'image.gif' or die "Cannot open: $!";
binmode IN;
print while ;
close IN;
There also needs to be an image called image.gif in the same directory (cgi-bin) as the cgi script.
I often use this technique to automatically perform certain text processing activities in my content management systems. For example, I might have one or more ASCII files that need to be automatically updated at the end of an operation, but I don't want to force the user to click, for example, an update button.
John Dixon is a web developer working through his own company John Dixon Technology. As well as providing web development services, John's company also provides 
