1<!DOCTYPE html> 2<html> 3 <head></head> 4 <body> 5 <h3> 6 Unmatched elements 7 </h3> 8 <p> 9 <span class="bold"><strong>[non-element]</strong></span> 10 </p> 11 <p> 12 [non-element] 13 </p> 14 </body> 15</html> 16