function validate() {

	var name = document.getElementById('name').value;
	var company = document.getElementById('company').value;
	var email = document.getElementById('email').value;
	var tel = document.getElementById('tel').value;
	var message = document.getElementById('message').value;
    var len_name = name.length;
    var len_company = company.length;
    var len_email = email.length;
    var len_tel = tel.length;
    var len_message = message.length;
	var email_valid = email.indexOf('@');
	if (name == '' || company == '' || email == '' || tel == '' || message == '') {
		alert('項目は全て必須となっております。');
		return false;
	}
	
	if (len_name > 100 || len_company > 100 || len_email > 100 || len_tel > 100 || len_message > 20000) {
		alert('項目は全て必須となっております。');
		return false;		
	}
	
	if (chkNumeric(tel)) {
		
	}
	else {
	 alert('電話番号は数値のみを入力ください。');
	 return false;	
	}

    if (email_valid < 0) {
	 alert('メールアドレスの形式が間違っています。');
	 return false;	
	}
	return true;

}

function chkNumeric(strString)
		//  check for valid numeric strings	
		{
			var strValidChars = "0123456789.";
			var strChar;
			var blnResult = true;
			
			if (strString.length == 0) return false;
			
			//  test strString consists of valid characters listed above
			for (i = 0; i < strString.length && blnResult == true; i++)
			{
				strChar = strString.charAt(i);
				if (strValidChars.indexOf(strChar) == -1)
				{
					blnResult = false;
				}
			}
			return blnResult;
		}