dators</h3>
         <section class="description"><h2>Description</h2>
            <p>HTML pages include a document type declaration (sometimes referred
    						to asÂ !DOCTYPE statement). The developer can use offline or online
    						validators (see Resources below) to check that attributes are only
    						used once on an element. The W3C validador, for example, will report   "duplicate
    						specification of attribute X" when it encounters the second definition
    						of the same attribu