According to the HTML 5 specification, "... if the element has a value attribute, it must return that attribute's value; otherwise, it must return the string "on"." In the case of HTML 4, this fix addresses malformed HTML. According to the HTML 4 specification, the value attribute is required for all input elements of type checkbox or radio. In cases where the value attribute is not provided (i.e., the HTML is malformed), all tested (i.e., modern) browsers default the value of the checkbox or radio to "on" if submitted with no value attribute.