function formcheck(myform)
{
  var err = 0;
	if(myform.field_data_1.value == "")
	{
		document.getElementById('error1').innerHTML = "This field is required."; 
		err = 1;
	}
	if(myform.field_data_2.value != '')
	{
    var email  = /(^[a-z]([a-z_\.]*)@([a-z_\.]*)([.][a-z]{3})$)|(^[a-z]([a-z_\.]*)@ ([a-z_\.]*)(\.[a-z]{3})(\.[a-z]{2})*$)/i;
	  if(!email.test(myform.field_data_2.value))
	  {
		  document.getElementById('error2').innerHTML = "It is not valid email address. Please re-enter it."; 
	    err = 1;
	  }
    else
    {
      document.getElementById('error2').innerHTML = '';
    }
  }
  else
  {
    document.getElementById('error2').innerHTML = '';
  }
	if(myform.field_data_2.value == "")
	{
		document.getElementById('error2').innerHTML = "This field is required."; 
		err = 1;
	}
	if(myform.field_data_3.value == "")
	{
		document.getElementById('error3').innerHTML = "This field is required."; 
		err = 1;
	}
	
  if(err == 0)
    return true;
  else
    return false;
}