function checkform ()
{
var form = document.getElementById('requestForm');

  if (form.firstName.value == "") {
    alert( "Please enter your First Name." );
    form.firstName.focus();
    return false ;
  }

  if (form.lastName.value == "") {
    alert( "Please enter your Last Name." );
    form.lastName.focus();
    return false ;
  }
  
  if (form.phone.value == "") {
    alert( "Please enter your Phone Number." );
    form.phone.focus();
    return false ;
  }
  
  if (form.email.value == "") {
    alert( "Please enter your Email Address." );
    form.email.focus();
    return false ;
  }

  if (form.address.value == "") {
    alert( "Please enter your Address." );
    form.address.focus();
    return false ;
  }

  if (form.city.value == "") {
    alert( "Please enter your City." );
    form.city.focus();
    return false ;
  }

  if (form.state.value == "") {
    alert( "Please enter your State." );
    form.state.focus();
    return false ;
  }

  if (form.zip.value == "") {
    alert( "Please enter your Zip Code." );
    form.zip.focus();
    return false ;
  }
     // prepare the form when the DOM is ready
          // bind form using ajaxForm
          $('#requestForm').ajaxForm({
              // target identifies the element(s) to update with the server response
              target: '#requestSamples',

              // success identifies the function to invoke when the server response
              // has been received; here we apply a fade-in effect to the new content
              success: function() {
                  $('#requestSamples').show();
              }
          });

  }