The resultIteration tag uses the following attributes:
formId. Specifies the name of the form associated with the search results. The default form is used if the attribute is left empty. If this tag is used without a form, this attribute must be set as a reference to the search tag.
start. Specifies an integer representing the starting position in the search results. The default is 0. The value is retrieved from the parent formAction tag or pageContext, or the parameter value.
numShown. Specifies an integer indicating the number of results to be shown in one page. The default is 20. The value is retrieved from the parent formAction tag or pageContext.