Overview |
The SoftPLC Web Server Weblet, along with Java Servlets and/or Applets can be used to build an operator interface that runs in a web browser. You can view various example web pages that utilize these techniques by connecting to a SoftPLC on the internet, a link is provided at http://www.softplc.com/webserver.php.
SoftPLC Corporation provides some very useful Servlets that enable you to build live web pages using only HTML. We've done the Java programming for you, you need only to build your HTML pages and configure the Servlet data.
The remainder of this document describes how to use the Servlets provided with the SoftPLC Web Server. This chapter describes the Servlets and the next chapter provides example HTML code, graphics and more to demonstrate how easy it is to build your browser based HMI.
Applets require Java programming and are beyond the scope of this document. If you are interested in using Applets, contact the SoftPLC Corporation sales department for information on existing applet shells and system integrators who can develop applets for you.
HTML | ||
What is HTML? H-T-M-L are initials that stand for HyperText Markup Language. It is a special kind of text document used by Web browsers to present text and graphics. The text includes markup tags such as <p> to indicate the start of a paragraph, and </p> to indicate the end of a paragraph. HTML documents are often referred to as "Web pages". The browser retrieves Web pages from Web servers, such as the one in SoftPLC.
If you don't know HTML, there are lots of good HTML tutorials, documents, manuals, etc. available for free on the internet. HTML shouldn't scare you, it is just text with tags. Another way to learn is to look at how other people have coded their html pages. To do this, click on the "View" menu and then on "Source". On some browsers, you instead need to click on the "File" menu and then on "View Source".
Many people still write HTML by hand using tools such as NotePad, or use their Word Processing program to save documents to HTML format. There are also many, many HTML WYSIWYG editors (What You See is What You Get) that make it much easier to ensure proper formatting and allow you to format your pages without having to know all the HTML markup tags.
One free, cross-platform WYSIWYG HTML editor is Mozilla Composer, which comes with Mozilla Suite. It is available at http://www.mozilla.org/products/mozilla1.x/.