1) <TD WIDTH=25%>
2) <TD WIDTH="25%">

XML, however, requires that all attribute values be enclosed with quotes. In other words, of the two examples above, only the second would be valid for XML, and then only presuming the ending </TD> tag was also present.
Some users say XML documents should have no attribute/value pairs, or very few, and others wish to convey a great deal of data in attribute/value pairs. The concept of attributes and attribute values will be explored later in this course.