function checkdata(){
    strUserID = document.evaluate.id.value;
	var newDateObj = new Date();

	function IsDigit(cCheck){  
      return (('0'<=cCheck) && (cCheck<='9'));  
    }
	
    function IsAlpha(cCheck){  
      return ((('a'<=cCheck) && (cCheck<='z')) || (('A'<=cCheck) && (cCheck<='Z')));  
    }

    function IsDecimal(decimal){
      for(nIndex=0; nIndex<decimal.length; nIndex++){                  
        cCheck = decimal.charAt(nIndex);
        if(!IsDigit(cCheck) && cCheck!="."){              
          return false;  
        }
	  }
	  return true;
    }

	function year2k(d){ 
      return (d < 1000) ? d + 1900 : d;
    }

	function isDate(year, month, day){      
       month = month - 1;
       var tempDate = new Date(year,month,day);
       if((year2k(tempDate.getYear())==year) && (tempDate.getMonth()==month) && (tempDate.getDate()==day)){
          return true;
       }else{
          return false;
       }
    }

	function check_date(somedate,focus_obj){
		somedatesplit=somedate.split("/",3);
		var someyear=somedatesplit[2];
		var somemonth=somedatesplit[0];
		var someday=somedatesplit[1];
		
		
		//if (isNaN(someyear) || someyear > newDateObj.getFullYear()  || someyear < 1800){
        if (isNaN(someyear) || someyear < 1800){
		  alert("请输入正确的年份");
		  focus_obj.focus();
		  return false;
		}

		if (isNaN(somemonth) || somemonth > 12  || somemonth < 1){
		  alert("请输入正确的月份");
		  focus_obj.focus();
		  return false;
		}

		if(isNaN(someday) || someday > 31  || someday< 1){
		  alert("请输入正确的日期");
		  focus_obj.focus();
		  return false;
		}
		
		if (!isDate(someyear,somemonth,someday)){
		   alert("日期组合错误,请检查您的日期组合。\r\n\r\n[提示，某些月份没有31日，二月没有30日，或没有29日]");
		   focus_obj.focus();
		   return false;
		}
		return true;
	}

	if(strUserID==""){
       alert("会员名不能为空");
	   document.evaluate.id.focus();
	   return false;
    }

	for (nIndex=0; nIndex<strUserID.length; nIndex++){                  
        cCheck = strUserID.charAt(nIndex);
        if (!(IsDigit(cCheck) || IsAlpha(cCheck) )){  
            alert("用户名只能使用英文字母、数字.");  
            document.evaluate.id.focus();  
            return false;  
        }
    }
    
	/*if(document.evaluate.studycontury.value==0){
       alert("请选择留学的国家");
	   document.evaluate.studycontury.focus();
	   return false;
    }*/
   
	if(document.evaluate.name.value==""){
       alert("姓名不能为空");
	   document.evaluate.name.focus();
	   return false;
    }

	bir=document.evaluate.birthday.value;
	bir_obj=document.evaluate.birthday;

	if(bir==""){
       alert("出生日期不能为空");
	   document.evaluate.birthday.focus();
	   return false;
    }

    if(!check_date(bir,bir_obj)){
		return false;		
    }

	var mail=document.evaluate.mailbox.value;
	if(mail==""){
       alert("邮箱不能为空");
       document.evaluate.mailbox.focus();
	   return false;
    }

	if(mail.indexOf("@")<0){
       alert("邮箱不正确");
       document.evaluate.mailbox.focus();
	   return false;
    }


    strTel=document.evaluate.tel.value;

	if(strTel==""){
       alert("电话不能为空");
	   document.evaluate.tel.focus();
	   return false;
    }

	for (in_Tel=0; in_Tel<strTel.length; in_Tel++){                  
        c_Tel = strTel.charAt(in_Tel);
        if ((!IsDigit(c_Tel)) && (c_Tel!="-")){  
            alert("电话只能使用数字和'-'.");
            document.evaluate.tel.focus();  
            return false;  
        }		
    }

    strHomeTel=document.evaluate.hometel.value;
	if(strHomeTel==""){
       alert("家庭电话不能为空");
	   document.evaluate.hometel.focus();
	   return false;
    }

    for (in_Tel=0; in_Tel<strHomeTel.length; in_Tel++){                  
        c_Tel = strHomeTel.charAt(in_Tel);
        if ((!IsDigit(c_Tel)) && (c_Tel!="-")){  
            alert("家庭电话只能使用数字和'-'.");
            document.evaluate.hometel.focus();  
            return false;  
        }
    }	

	var thedate=document.evaluate.collegegraduatetime.value;
	var thedate_obj=document.evaluate.collegegraduatetime;
    if(thedate!=""){
      if(!check_date(thedate,thedate_obj)){
		return false;		
      }
	}

	var thedate=document.evaluate.highgraduatetime.value;
	var thedate_obj=document.evaluate.highgraduatetime;
    if(thedate!=""){
      if(!check_date(thedate,thedate_obj)){
		return false;		
      }
	}

    var toefl_obj=document.evaluate.toefl.value;
	if(toefl_obj!=""){
 	 if(isNaN(toefl_obj)){
		alert("成绩只能为数字");
		document.evaluate.toefl.focus();
		return false;
	 }
    }

    var thedate=document.evaluate.toefltime.value;
	var thedate_obj=document.evaluate.toefltime;
    if(thedate!=""){
      if(!check_date(thedate,thedate_obj)){
		return false;		
      }
	}
   
    var ielts_obj=document.evaluate.ielts.value;
	if(!IsDecimal(ielts_obj)){
        alert("雅思成绩只能为数字或小数点");
		document.evaluate.ielts.focus();
		return false;
	}
    
	var thedate=document.evaluate.ieltstime.value;
	var thedate_obj=document.evaluate.ieltstime;
    if(thedate!=""){
      if(!check_date(thedate,thedate_obj)){
		return false;		
      }
	}

    var gre_obj=document.evaluate.gre.value;
	if(gre_obj!=""){
 	 if(isNaN(gre_obj)){
		alert("成绩只能为数字");
		document.evaluate.gre.focus();
		return false;
	 }
    }

    var thedate=document.evaluate.gretime.value;
	var thedate_obj=document.evaluate.gretime;
    if(thedate!=""){
      if(!check_date(thedate,thedate_obj)){
		return false;		
      }
	}

	var gmat_obj=document.evaluate.gmat.value;
	if(gmat_obj!=""){
 	 if(isNaN(gmat_obj)){
		alert("成绩只能为数字");
		document.evaluate.gmat.focus();
		return false;
	 }
    }

	var thedate=document.evaluate.gmattime.value;
	var thedate_obj=document.evaluate.gmattime;
    if(thedate!=""){
      if(!check_date(thedate,thedate_obj)){
		return false;		
      }
	}

	var german_obj=document.evaluate.german.value;
	if(german_obj!=""){
 	 if(isNaN(german_obj)){
		alert("成绩只能为数字");
		document.evaluate.german.focus();
		return false;
	 }
    }

	var thedate=document.evaluate.germantime.value;
	var thedate_obj=document.evaluate.germantime;
    if(thedate!=""){
      if(!check_date(thedate,thedate_obj)){
		return false;		
      }
	}	

    var french_obj=document.evaluate.french.value;
	if(french_obj!=""){
 	 if(isNaN(french_obj)){
		alert("成绩只能为数字");
		document.evaluate.french.focus();
		return false;
	 }
    }

	var thedate=document.evaluate.frenchtime.value;
	var thedate_obj=document.evaluate.frenchtime;
    if(thedate!=""){
      if(!check_date(thedate,thedate_obj)){
		return false;		
      }
	}
    
    var japanese_obj=document.evaluate.japanese.value;
	if(japanese_obj!=""){
 	 if(isNaN(japanese_obj)){
		alert("成绩只能为数字");
		document.evaluate.japanese.focus();
		return false;
	 }
    }

	var thedate=document.evaluate.japanesetime.value;
	var thedate_obj=document.evaluate.japanesetime;
    if(thedate!=""){
      if(!check_date(thedate,thedate_obj)){
		return false;		
      }
	}

	var thedate=document.evaluate.beginstudytime.value;
	var thedate_obj=document.evaluate.beginstudytime;
    if(thedate!=""){
      if(!check_date(thedate,thedate_obj)){
		return false;		
      }
	}
	    
    var themoney=document.evaluate.assuremoney.value;	
    if(themoney!=""){
      if(!IsDecimal(themoney)){
        alert("担保资金只能为数字或小数点");
		document.evaluate.assuremoney.focus();
		return false;
      }
	}

	if(document.evaluate.assuremanduty.value==""){
       alert("担保人职务不能为空");
	   document.evaluate.assuremanduty.focus();
	   return false;
    }

	if(document.evaluate.selfduty.value==""){
       alert("本人职务不能为空");
	   document.evaluate.selfduty.focus();
	   return false;
    }

    return true;
  }