function checking(){
	var err=false, errMsgMan="", errMsgEmail="", errMsgDate2="", errMsgGrant=""; 
	if ( (document.form1.NameFirst.value=="") )
		errMsgMan = errMsgMan + "請填寫您的名字\n";

	if ( (document.form1.NameLast.value=="") )
		errMsgMan = errMsgMan + "請填寫您的姓氏\n";

	if ( (document.form1.Gender.options[document.form1.Gender.selectedIndex].value=="-") )
		errMsgMan = errMsgMan + "請選擇您的性別\n";

	if ( (document.form1.Age.options[document.form1.Age.selectedIndex].value=="-") )
		errMsgMan = errMsgMan + "請選擇您的年齡組別\n";

	if ( (document.form1.Email.value=="") )
		errMsgMan = errMsgMan + "請填寫您的電郵地址\n";	

	if (document.form1.Email.value!= "" ) { //check whether email provided is valid
		if ( !emailcheckOK(document.form1.Email.value) ) {
			err=true;
			errMsgEmail = "請提供一個正確電郵地址\n\n";
		}		
	}

	if ( (document.form1.ContactNo.value=="") )
		errMsgMan = errMsgMan + "請填寫您的聯絡電話號碼\n";

	if ( isNaN(document.form1.ContactNo.value) || (document.form1.ContactNo.value.length < 8) || (document.form1.ContactNo.value.length > 11) )
		errMsgMan = errMsgMan + "請提供一個正確電話號碼\n";

	if ( (document.form1.Address.value=="") )
		errMsgMan = errMsgMan + "請填寫您的聯絡地址\n";	

	if ( (document.form1.HearFrom.options[document.form1.HearFrom.selectedIndex].value=="-") )
		errMsgMan = errMsgMan + "閣下如何得知此網站?\n";

	if(errMsgMan != "")
		err=true;

	errBrochure = true;
	errMsgBrochure = "";
	for (var i=0; (i<document.form1.brochure_of.length && errBrochure); i++) {
		if (document.form1.brochure_of[i].checked) {
			errBrochure=false;
		}
	}
	if (errBrochure) {
		err=true;
		errMsgBrochure="請選擇您想索取的汽車簡介\n";
	}

	if (!document.form1.Option_Grant.checked) {
		err=true;
		errMsgGrant="閣下還未審閱 / 同意接納本網站之試車條款及細則";
	} 

	if (err == true)  {
		alert (errMsgMan + errMsgEmail + errMsgBrochure + errMsgGrant);
	} else {
		if (document.form1.JobTitle.value=="-") { document.form1.JobTitle.value=""} ;
		document.form1.submit();
	}
	return false;
}

function emailcheckOK(str) {

		var at="@"
		var dot="."
		var lat=str.indexOf(at)
		var lstr=str.length
		var ldot=str.indexOf(dot)
		if (str.indexOf(at)==-1){
		   return false
		}

		if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
		   return false
		}

		if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
		    return false
		}

		 if (str.indexOf(at,(lat+1))!=-1){
		    return false
		 }

		 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		    return false
		 }

		 if (str.indexOf(dot,(lat+2))==-1){
		    return false
		 }
		
		 if (str.indexOf(" ")!=-1){
		    return false
		 }

 		 return true					
	}

/**
 * DHTML date validation script. Courtesy of SmartWebby.com (http://www.smartwebby.com/dhtml/)
 */
// Declaring valid date character, minimum year and maximum year
var dtCh= "/";
var minYear=1900;
var maxYear=2100;

function isInteger(s){
	var i;
    for (i = 0; i < s.length; i++){   
        // Check that current character is number.
        var c = s.charAt(i);
        if (((c < "0") || (c > "9"))) return false;
    }
    // All characters are numbers.
    return true;
}

function stripCharsInBag(s, bag){
	var i;
    var returnString = "";
    // Search through string's characters one by one.
    // If character is not in bag, append to returnString.
    for (i = 0; i < s.length; i++){   
        var c = s.charAt(i);
        if (bag.indexOf(c) == -1) returnString += c;
    }
    return returnString;
}

function daysInFebruary (year){
	// February has 29 days in any year evenly divisible by four,
    // EXCEPT for centurial years which are not also divisible by 400.
    return (((year % 4 == 0) && ( (!(year % 100 == 0)) || (year % 400 == 0))) ? 29 : 28 );
}
function DaysArray(n) {
	for (var i = 1; i <= n; i++) {
		this[i] = 31
		if (i==4 || i==6 || i==9 || i==11) {this[i] = 30}
		if (i==2) {this[i] = 29}
   } 
   return this
}

function isDate(dtStr){
	var daysInMonth = DaysArray(12)
	var pos1=dtStr.indexOf(dtCh)
	var pos2=dtStr.indexOf(dtCh,pos1+1)
	var strDay=dtStr.substring(0,pos1)
	var strMonth=dtStr.substring(pos1+1,pos2)
	var strYear=dtStr.substring(pos2+1)
	strYr=strYear
	if (strDay.charAt(0)=="0" && strDay.length>1) strDay=strDay.substring(1)
	if (strMonth.charAt(0)=="0" && strMonth.length>1) strMonth=strMonth.substring(1)
	for (var i = 1; i <= 3; i++) {
		if (strYr.charAt(0)=="0" && strYr.length>1) strYr=strYr.substring(1)
	}
	month=parseInt(strMonth)
	day=parseInt(strDay)
	year=parseInt(strYr)
	if (pos1==-1 || pos2==-1){
		//alert("The date format should be : mm/dd/yyyy")
		return ("The date format should be dd/mm/yyyy");//false
	}
	if (strMonth.length<1 || month<1 || month>12){
		//alert("Please enter a valid month")
		return ("Please enter a valid month");//false
	}
	if (strDay.length<1 || day<1 || day>31 || (month==2 && day>daysInFebruary(year)) || day > daysInMonth[month]){
		//alert("Please enter a valid day")
		return ("Please enter a valid day");//false
	}
	if (strYear.length != 4 || year==0 || year<minYear || year>maxYear){
		//alert("Please enter a valid 4 digit year between "+minYear+" and "+maxYear)
		return ("Please enter a valid 4 digit year between "+minYear+" and "+maxYear);//false
	}
	if (dtStr.indexOf(dtCh,pos2+1)!=-1 || isInteger(stripCharsInBag(dtStr, dtCh))==false){
		//alert("Please enter a valid date")
		return ("Please enter a valid date"); //false
	}
return '';
}