Another specialty selector is the ID selector. Like the class, an ID selector
is based on the value of an attribute, but in this case, it's the ID attribute. This
selector is used to single out a particular element; IDs should be unique within a
document. For example the following code in Listing 6 selects the span designated as
bestinshow by preceding the name with a pound sign
#) and colors it red, as shown in Figure 5.