function register_check_all(){
	this.mail = false;
	this.ymail = false;
	this.subject = false;
    this.mailbody = false;
}

var bln_check = new register_check_all();

function check_mail(){
	byId('mail_e').style.display='none';
	byId('mail_n').style.display='none';
	var str=byId('mail').value;
	if(isEmpty(str)){
			byId('mail_e').style.display='block';
			bln_check.mail = false;
	}else{
		if (isEmail(str)){
			bln_check.mail = true;
		}else{
			byId('mail_n').style.display='block';
			bln_check.mail = false;		
		}		
	}

}

function check_ymail(){
	byId('ymail_e').style.display='none';
	byId('ymail_n').style.display='none';
	var str=byId('ymail').value;
	if(isEmpty(str)){
			byId('ymail_e').style.display='block';
			bln_check.ymail = false;	
	}else{
		if (isEmail(str)){
			bln_check.ymail = true;
		}else{
			byId('ymail_n').style.display='block';
			bln_check.mail = false;	
		}
	}
}

function check_subject(){
	var str=byId('subject').value;
	byId('subject_e').style.display='none';
	if (isEmpty(str)){
		byId('subject_e').style.display='block';
		bln_check.subject=false;
	}else{
		bln_check.subject = true;
	}
}

function check_mailbody(){
	var str=byId('mailbody').value;
	byId('mailbody_e').style.display='none';
	if (isEmpty(str)){
		byId('mailbody_e').style.display='block';
		bln_check.mailbody=false;
	}else{
		bln_check.mailbody = true;
	}
}

function on_submit(){
	check_mail();
	check_ymail();
	check_subject();
	check_mailbody();

	if( bln_check.mail == true && bln_check.ymail == true && bln_check.subject == true && bln_check.mailbody == true){
		return true;
	}else{
		return false;
	}	
}