What's the Impact?

So, how does the choice of a particular doctype impact a Logi application? It can have quite an impact. XHTML Frameset provides a "loose" standard that encompasses everything, and the HTML generated by the Logi Server Engine did not generally cause any DTD-related problems. The default option, HTML5, may result in significant rendering differences in different browsers. And, if you select None, meaning use no doctype, you will almost certainly see presentation (CSS) differences between browsers. Things won't always be aligned correctly, and style may not be applied where or how you expect it, with the most problems occurring in Internet Explorer. And, in complimentary action, if you are seeing differences in the way different browsers present your report pages, the use of a doctype may fix that.

You should be aware that, when you upgrade an application to Logi v12, and then open and edit legacy report definitions, Studio will automatically insert the default doctype, HTML5, depending on Logi version, into the definitions. This will often cause CSS to work differently and the resulting reports may look different. Developers who don't want to tweak their reports to "correct" these effects, can set the doctype to None in order to return the reports to their original appearance. Prior to HTML5, standards evangelists called for developers to use the XHTML Strict doctype whenever possible. This "tight" standard requires that you code everything very correctly. For example, if you use Event Handler with Action.Javascript or Action.Link and Target.Link elements (earlier versions) in your Logi app, and add Javascript, you must use the correct case-sensitive spelling for any Javascript functions there. This means "getElementById()" will work, but "GetElementByID()" will not. Your choice of doctype will also affect any HTML documents that you choose to embed in your Logi application. In this case, because the HTML is not being generated by the Log Server Engine, you need to take care to ensure that the coding is compliant with the doctype you've selected. For example, if your embedded HTML document includes the <font> tag and you select the Strict doctype, the tag will be ignored because that doctype does not support presentation-related tags within the HTML. If you are new to HTML5 and wish to see which of its features are available with which browsers, see this website: http://www.CanIUse.com.