function check(form){
	//宣告array
	var rec_name_array = new Array();
	var rec_mail_array = new Array();
	
	//計算msg長度
	var msgN = document.InputForm.msg.value.length;
	
	//計算rec[]及recmail[]，去除空值
	var rec_name_number = 0;
	var rec_mail_number = 0;
	for(i=0; i<3;i++){
		if((form.elements[i].value)!=""){
			rec_name_number = rec_name_number + 1;
			}
		}
	for(i=0; i<3;i++){
		if((form.elements[i+3].value)!=""){
			rec_mail_number = rec_mail_number + 1;
			}
		}
			
	//存入rec[]及recmail[]
	for(i=0; i<rec_name_number;i++){
		rec_name_array[i] = form.elements[i].value;
		}
	for(i=0; i<rec_mail_number;i++){
		rec_mail_array[i] = form.elements[i+3].value;
		}
		
	//表單檢查
	if(rec_name_number == 0){
		alert("Friend's Name field is required");
		form.elements[0].focus();
		return false;				
		}
	if(rec_mail_number == 0){
		alert("Friend's E-mail field is required");
		form.elements[3].focus();
		return false;				
		}
	if(rec_name_number != rec_mail_number){
		text = rec_name_number + " friends\n" + rec_mail_number + " emails\n\n" + "Data Error!!";
		alert(text);
		form.elements[0].focus();
		return false;				
		}
		
	for(i=0; i<rec_name_number;i++){
		if(rec_mail_array[i].indexOf('@', 0) == -1){
			alert("E-mail format incorrect: " + rec_name_array[i] + "<" + rec_mail_array[i] + ">");
			form.elements[i+3].focus();
			return false;			
			}			
		}
		
	if(form.from_name.value==""){
		alert("Your Name field is required");
		form.from_name.focus();
		return false;			
		}
	if(form.from_email.value==""){
		alert("Your E-mail field is required");
		form.from_email.focus();
		return false;			
		}
	if(form.from_email.value.indexOf('@', 0) == -1){
		alert("Your E-mail format is incorrect");
		form.from_email.focus();
		return false;			
		}
		
	if(msgN == 0){
		alert("Message field is required");
		form.msg.focus();
		return false;		
		}
		

	return true;
	}