function checkDate(dateStr){
		if (!isDate(dateStr)){
			return false;
		}
			return true;
	}
	
	function isNumeric(num){
		var d = num;
		var regexp= /^(\d{1,3})$/;
		if (!regexp.test(d)){
			return false;		
		}	
		return true;
	}
function isDate(dateStr){
	var d = dateStr;
	var regexp = /^(-\d{1,4}\/\d{1,2}\/\d{1,2}|\d{1,4}\/\d{1,2}\/\d{1,2})$/;
	if (!regexp.test(d)){
		return false;
	}


//convert string format to numeric format
	var year = dateStr2Year(dateStr);
	var month = dateStr2Month(dateStr);
	var day = dateStr2Day(dateStr);
// check legal month
	if ((month < 1 )||(month > 12)){
		return false;
	}
// check legal day
	if (day < 1 ) {
		return false;
	}
// check date range	
	if (year<1753){
		return false;
	}
	
//
	if (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)){
		var dayOfMonthArray = new Array(31,29,31,30,31,30,31,31,30,31,30,31);
	}else{
		var dayOfMonthArray = new Array(31,28,31,30,31,30,31,31,30,31,30,31);
	}
//
	if (day > dayOfMonthArray[month-1]){
			return false;
	}
	return true;
}
//
function dateStr2Year(dateStr){
// convert date string to year 
	return parseInt(dateStr.substring(0,dateStr.indexOf("/")),10) ;
}
//
function dateStr2Month(dateStr){
// convert date string to month
	var begi = dateStr.indexOf("/") + 1;
	var endi = dateStr.indexOf("/",begi);
	return parseInt(dateStr.substring(begi,endi),10);
}
//
function dateStr2Day(dateStr){
// convert date string to day
	return parseInt(dateStr.substring(dateStr.lastIndexOf("/")+1),10);
}

//"  abc"
function ltrim(s){
	while(s.substring(0,1) == " "){
		s = s.substring(1);
	}
	return s;
}

function rtrim(s){
	while(s.substring(s.length-1,s.length) == " "){
		s = s.substring(0,s.length-1);
	}
	return s;
}

function trim(s){
	return ltrim(rtrim(s));
}



function isPersonalId(idStr){


 var id = trim(idStr);

 var regexp = /^(\D{1}\d{9})$/;
 if(!regexp.test(id)){
	alert("身分証字號錯誤");
	return false;
 }

 var idCode = new Array(10,11,12,13,14,15,16,17,34,18,19,20,21,22,35,23,24,25,26,27,28,29,32,30,31,33);
 var checkCode = idCode[parseInt(id.substring(0,1),36)-10];
 var checksum = parseInt(checkCode/10) + ((checkCode%10)*9);

 for(var i =1;i<9;i++){
  checksum +=(parseInt(id.substring(i,i+1))*(9-i));
 }
 checksum += parseInt(id.substring(i,i+1));

 if(!((checksum%10)==0)){
	alert("身分証字號錯誤");
	return false;
 }
	return true;
}

function Str_len(Str1,Str1_1,Len1){
	Str1=trim(Str1);
	if (Str1.length > Len1){
		alert(Str1_1+' 不可大於 '+Len1+' 個字元!');
		return false;
	}
	return true;
}

function chk_vote(form){
			var fl=0;
			for (i=0;i<form.Sel.length;i++){
				if (form.Sel[i].checked==true){
					fl=1;
					break;
				}
			}	
			if (fl==0){
				alert("請選擇投票項目!!");
				return false;
			} //if
		
			return true;
} 
function checkField(f){
	var u=trim(f.USER_ID.value);
	if(u==""){
		alert("請輸入登入名稱");
		f.USER_ID.focus();
		return false;
	}
	var p=trim(f.PASSWORD.value);
	if(p==""){
		alert("請輸入登入密碼");
		f.PASSWORD.focus();
		return false;
	}
	f.submit();
	return true;
}