function checkinput(){
	if(document.contactform.name1.value == '' ||
	   document.contactform.mail1.value == '' ||
	   document.contactform.message.value == ''

	){
		document.contactform.name1.style.backgroundColor='#ffffff';
		document.contactform.mail1.style.backgroundColor='#ffffff';
		document.contactform.message.style.backgroundColor='#ffffff';

		if(document.contactform.name1.value == ''){
			document.contactform.name1.style.backgroundColor='#ffffb3';
		}
		if(document.contactform.mail1.value == ''){
			document.contactform.mail1.style.backgroundColor='#ffffb3';
		}
		if(document.contactform.message.value == ''){
			document.contactform.message.style.backgroundColor='#ffffb3';
		}
		alert("必須項目が入力されていません。");
		return false;
	}else{
		return true;
	}
}