Validator-Lite for Desktop

Validator-Lite is a simple but formally rigorous validator, based on the same OpenSP parser used by all the main validators, such as the W3C Validator, the WDG Validator, and Page Valet. This desktop tool serves to validate HTML, XHTML and DTD-based XML document types, although it lacks the extended XML capabilities of WebÞing's multi-parser products Site Valet Enterprise Edition or mod_validator.

The Validator Display

[validator screenshot] The screenshot shows Validator-Lite. At the top is an entry box labelled File or URL where you should enter the filename or URL of a document to validate. A Browse button is provided to help browse local files. Below the File/URL entry box are the secondary controls to select Parse Mode and Encoding. These are followed by a Validate button, that generates a report on the selected document.

Below the controls, the major part of the Validator is the results display. Errors and warnings in the document validated will be displayed here. Each message occupies four columns: the first is a single-letter code indicating the type of message; the second and third show the line and column in the markup where the message was generated, while the final column (occupying most of the display width) displays a descriptive warning or error message.

Finally, at the bottom of the display, a status bar is used to display summary validation results and system messages. It is flanked by two final controls: a Help button and a Quit button.

Parse Mode Selection

Four parse modes are offered. Three of them correspond to the OpenSP parse modes offered by Page Valet, while the fourth (XML/XHTML) is required for XHTML and other XML pages, as these are not automatically detected by Validator-Lite. For XML and XHTML documents you must select XML/XHTML mode; for HTML you must not select it!

Strict SGML

Strictly speaking, this is the only mode that offers true HTML validation. However, this allows various constructs that will break in most mainstream browsers, and should be used with caution.

For example, the following is a valid HTML document:

	<title/HTML example/
	<p<p/This is the second paragraph in this document.
	The first was empty.

Note the missing >s - this will confuse browsers!


HTML Mode will generate additional warnings about these quirks, and is strongly recommended for HTML documents.

Fussy Mode

Fussy mode adds further checks over and above HTML Mode. These are, in our view, seldom necessary, but may be considered Good Practice. The main effect is to cause the validator to insist on tags that are implied by your markup being made explicit.


XML (and therefore XHTML) doesn't have the kind of quirks discussed above. Selecting this mode serves to select the XML Catalogue and to parse in XML mode.


Validator-Lite doesn't support the sophisticated methods for detecting document encoding used by Site Valet or mod_validator. Instead it offers you the opportunity to select an encoding. If you do not select an encoding, OpenSP will do its best, but may produce erroneous results (although it's unlikely to make any difference in English-language pages).

Note that XML has complete rules for detecting document encoding, which will be applied if you select XML/XHTML parse mode or the "xml" option in the Encoding menu.

Installation and Setup

Please see the separate installation page.