function check_form(fromname)
	{var Errmessage;
		Errmessage=''
	 validity = true;
	 varForm=document.getElementById(fromname);
	 
	 	if (varForm.Province.value=='')
	 		{validity=false; Errmessage=Errmessage+'省/直辖市不能为空！';}

	 	if (varForm.City.value=='')
	 		{validity=false; Errmessage=Errmessage+'城市不能为空！';}

	 	if (District.value=='')
	 		{validity=false; Errmessage=Errmessage+'请选择区县！';}

	 if (!validity)
	 	alert(Errmessage);
  	return validity;
  	}
  	
function clear(obj1){
len=obj1.length;
for (i = 0; i < len; i ++){
	obj1.options[0]=null;
}
}

function fullup(obj1,val){
var vn = new Option(val,val); 
    obj1.add(vn);
}

function sel(val,obj){
	for (i=0;i<obj.length;i++){
		if (obj[i]==val){
			return i;
			}
		}
	if (i==obj.length){return 0;}
}


function SelectProvince(Formname)
{
varForm=document.getElementById(Formname);
pbox=varForm.Province;
cbox=varForm.City;
dbox=varForm.District;
val=pbox.value;

if (val!=""){
		err=1;
		m=sel(val,P);
		clear(cbox);
		

for (i=0;i<C[m].length;i++){fullup(cbox,C[m][i])}
		clear(dbox);
		fullup(dbox,"");
		for (i=0;i<D[m][0].length;i++){fullup(dbox,D[m][0][i])}
		
		
	}
	else{
		clear(cbox);
		clear(dbox);
		
		fullup(cbox,"请选择")
		fullup(dbox,"请选择")
		
	}
}
function SelectCity(Formname)
{
varForm=document.getElementById(Formname);
 cbox=varForm.City;
 dbox=varForm.District;
 if (err==0){alert("请您选择省/城市!");}
 else{
 	cval=cbox.value;
 	n=sel(cval,C[m]);
 	clear(dbox);
 	fullup(dbox,"");
 	for(i=0;i<D[m][n].length;i++){fullup(dbox,D[m][n][i])}
	
	}
}