Perl cgi script for validating and updating database
To check if a username is taken, the code reads the file and compares each line to the passed-in value, case-insensitively.
Anything you can do in Perl that you couldn’t in Java Script now becomes possible. Because this is such a wildly popular application, the username you want is probably taken.
Unfortunately, you have to resubmit the entire form and wait for the server to receive it before being told that you can’t have the username can help you to solve this?
It starts off like all good Perl code, by using the deals with putting together bits of HTML. If so, the code checks that it looks good and records that username in our database.
For a real-world script, use something like HTML:: Template or Template Toolkit instead of putting HTML directly in the script. If there were any problems, it mentions those as well.
At the core, Ajax techniques let you update parts of your web page without reloading the whole page from scratch. Many people cite Google Maps and Gmail as great examples of what you can do with this, but my favorite bit of Ajax is part of Flickr.