Nowadays, advertising companies and firms try to establish a trade name which is superior to similar ones. In order to overcome their competitors in advertising campaigns, the firms have adopted new approaches. They use the best and newest marketing and commercial advertising methods to attract potential customers and consumers. Some advertisers use their competitors' trademarks, trade name, etc. to advertise their goods and services. This kind of advertisements which has increased considerably, is known as comparative advertising and makes it possible for consumers to compare the characteristics of different brands including the quality and price of goods and services and at the same time, in some cases may mislead consumers as to the source of goods and services and lead to unfair competition...