There is an error with select evenment on IE8 rc1 for the validate plugin.

The error come from method required: function(value, element, param)

where options[0].attributes['value'] is null so options[0].attributes['value'].specified throw an error.

With IE8, the method to get a select value seems to have changed.

A workaround is to add &&($.browser.version<8)

into:

return options.length > 0 && ( element.type == "select-multiple" || ($.browser.msie && !(options[0].attributes['value'].specified) ? options[0].text : options[0].value).length > 0);

so the result work :

return options.length > 0 && ( element.type == "select-multiple" || ($.browser.msie && ($.browser.version<8) && !(options[0].attributes['value'].specified) ? options[0].text : options[0].value).length > 0);