There are a number of ways to make the forms on your website more user friendly. This article will explain one way of doing this, which eliminates a page reload and replaces it with an image generated on the server.
Submitting a Form Using an Image Tag (Page 1 of 8 )
Forms on the Web are somewhat user unfriendly. One of the worst parts of using a form on a website is page reloads. Many times, after submitting a form, you are taken to a confirmation page, which provides links to go somewhere else rather then allowing you to submit the information and get on with your life.
There are many server side Web application platforms that provide a way to generate graphics "on the fly" either built into the application language or via some sort of extension.
Most of these systems work with HTML in a very simple manner. Rather than using a path to an image in the src attribute of an image tag, the path to a coded page is used. This coded page (such as a PHP or ASP page) generates the graphics, assembles the proper HTTP headers and then sends the response as an image rather than an HTML document.
Many times this is used to display bar graphs, pie charts or other graphics assembled using information in a database.
Since we are sending the request to a Web application, there is nothing that says that we can't send more than just the path to the application.
In a standard GET style HTTP request (like a page request), a query string is used to send additional information to the server. A query string is made up of a "?" character followed by one or more name/value pairs separated by an "&", and encoded to escape characters such as spaces that are not allowed in URLs.
A query string can be appended to any URL. As long as the target of the request is able to process and use the query string, then we have something useful. A static image of course has no use for query strings; a Web application can do quite a lot with one, however.