function validate(form_id,email) {
   var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
   var address = document.forms[form_id].elements[email].value;
   if(reg.test(address) == false) {
      alert('Invalid Email Address');
      return false;
   }
}


function checkform(form){	
	if (form.name.value == "") {
    alert( "Please enter your Name here" );
    form.name.focus();
    return false ;
  }
  
  if (form.user_email.value == "") {
    alert( "Please enter your Email here" );
    form.user_email.focus();
    return false ;
  }
  
  if (form.user_email.value != "") {
    var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
   	var address = form.user_email.value;
   	if(reg.test(address) == false) {
      alert('Invalid Email Address');
	  form.user_email.focus();
      return false;
   	}
  }
  
  if (form.invoice.value == "") {
    alert( "Please enter your invoice Number here" );
    form.invoice.focus();
    return false ;
  }
  
  
  if (form.date.value == "") {
    alert( "Please select your Purchased date here" );
    form.date.focus();
    return false ;
  }
  
  if (form.month.value == "") {
    alert( "Please select your Purchased month here" );
    form.month.focus();
    return false ;
  }
  
  if (form.year.value == "") {
    alert( "Please select your Purchased year here" );
    form.year.focus();
    return false ;
  }
  
  if (form.product.value == "") {
    alert( "Please select your product here" );
    form.product.focus();
    return false ;
  }
	
}



function checkform_c(form){	
	if (form.name.value == "") {
    alert( "Please enter your Name here" );
    form.name.focus();
    return false ;
    }
	
	if (form.user_email.value == "") {
    alert( "Please enter your Email here" );
    form.user_email.focus();
    return false ;
  }
  
  if (form.user_email.value != "") {
    var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
   	var address = form.user_email.value;
   	if(reg.test(address) == false) {
      alert('Invalid Email Address');
	  form.user_email.focus();
      return false;
   	}
  }
  
  if (form.product.value == "") {
    alert( "Please select your product here" );
    form.product.focus();
    return false ;
  }
  
}