function address(){
    	/*请在此补充代码*/
    var sf=document.getElementById("sf");
    var sq=document.getElementById("sq");
    var arrSf=new Array("北京市","天津市","河北省","河南省");
    var arrSq=new Array("朝阳区","西城区","西青区","武清区","石家庄","邯郸市","郑州市","开封市");
    for(var x=0;x<arrSf.length;x++)
    {
        selectAdd(sf,arrSf[x],x);
    }
    for(var y=0;y<arrSq.length;y++)
    {
        selectAdd(sq,arrSq[y],y);
    }
}
function selectAdd(obj,name,value){
		/*请在此补充代码*/  
	obj.options.add(new Option(name,value));
}
function linkage(){
	/*请在此补充代码*/ 
	var sf=document.getElementById("sf");
    var sq=document.getElementById("sq");
    var arrSf = new Array("北京市","天津市","河北省","河南省");
    var arrSq = new Array("朝阳区","西城区","西青区","武清区","石家庄","邯郸市","郑州市","开封市");
        switch(sf.value*1)
        {

            case 0:
                sq.options.length=0;
                selectAdd(sq,arrSq[0],0);
                selectAdd(sq,arrSq[1],1);
                break;
            case 1:
                sq.options.length=0;
                selectAdd(sq,arrSq[2],2);
                selectAdd(sq,arrSq[3],3);
                break;
            case 2:
                sq.options.length=0;
                selectAdd(sq,arrSq[4],4);
                selectAdd(sq,arrSq[5],5);
                break;
            case 3:
                sq.options.length=0;
                selectAdd(sq,arrSq[6],6);
                selectAdd(sq,arrSq[7],7);
                break;
            default:
                break;
        }