[tikhon_shw]

Все спасибо!! получилось.. результат:

var form=document.forms['myform'];
  var numberSelected = 0;
  var emptyInput = 0;
  for(var i=0;i<form.elements.length;i++)
  { if(form.elements[i].style.background == "#feafc4")
    { numberSelected++; }
  }
  if (numberSelected == 0) formObj.myButon.disabled = false; else formObj.myButon.disabled = true;