When using the Logi Studio, many elements allow for an attribute named [Class] – this value is calling a class element from a stylesheet or <style> element included in the document. 

The Class attribute of an element can contain multiple values.  This can be done by entering the class names manually or selecting them from a pulldown list in the IDE.  If the user [CTRL] clicks this list of values, multiple values will be placed into the construct.

When using the [CTRL] click feature within the Logi Studio, the studio will ‘comma’ separate the values in the Class element.

According to the W3C these commas should be removed to adhere to the W3C recommendations of HTML Best Practices:

.5.2 Element identifiers: theidandclassattributes

Attribute definitions

id= name [CS]

This attribute assigns a name to an element. This name must be unique in a document.

class= cdata-list [CS]

This attribute assigns a class name or set of class names to an element. Any number of elements may be assigned the same class name or names. Multiple class names must be separated by white space characters ( https://www.w3.org/TR/html401/struct/global.html#h-7.5.2 )

 

And from the HTML5 specification ( https://www.w3.org/TR/html5/dom.html#classes ) :

3.2.5.7 The class attribute

Every HTML element may have a class attribute specified.

The attribute, if specified, must have a value that is a set of space-separated tokens representing the various classes that the element belongs to.

The classes that an HTML element has assigned to it consists of all the classes returned when the value of the class attribute is split on spaces. (Duplicates are ignored.)

2.4.7 Space-separated tokens

A set of space-separated tokens is a string containing zero or more words (known as tokens) separated by one or more space characters, where words consist of any string of one or more characters, none of which are space characters.