function checker()
{
var fname = document.getElementById ('FName');
var Company = document.getElementById ('Company');
var Phone = document.getElementById ('Phone');
var Email = document.getElementById ('Email');

var fsubmit = document.getElementById ('FSubmit');


if (fname.value!= "" && Company.value!= "" && Phone.value!= "" && Email.value!= "") {
                         fsubmit.disabled = false;
                         }
                         else {
                         fsubmit.disabled = true;
                         }

}