After running Functional Accessibility Evaluator 1.1 from The University of Illinois at Urbana-Champaign on the boldy.d7.garethalexander.co.uk demo site.
Under Navigation & Orientation in the Form Control Labels section there is:
Fail: 31 pages (of 31) with this error
Each input element with type=button | submit | reset must have either a value attribute or a title attribute.
Comments
Comment #1
the_g_bomb commentedSee http://html.cita.illinois.edu/nav/form/ for best practices
Comment #2
the_g_bomb commentedAdded some styling to the search form submit button, so that I can add the value back into the button without it showing up over the image that is being used.