Currently, the third-level connections seen on the Internet are generally connected to databases or, using JavaScript Arrays for third-level linkages. I don't think this is necessary for data. It seems a bit cool and inconvenient to modify. Javascript arrays are not so easy to understand for beginners and are not easy to modify. XML is a good choice. It is very convenient to add and delete the arrays!
Provincecity. xml
<? XML version = "1.0" encoding = "UTF-8"?>
<Root>
<Province name = "Beijing" id = "110000">
<City name = "city jurisdiction" id = "110100">
<Area name = "Dongcheng District" id = "110101"/>
<Area name = "Xicheng district" id = "110102"/>
<Area name = "Chongwen District" id = "110103"/>
<Area name = "Xuanwu District" id = "110104"/>
<Area name = "Chaoyang District" id = "110105"/>
<Area name = "Fengtai District" id = "110106"/>
<Area name = "Shijingshan district" id = "110107"/>
<Area name = "Haidian District" id = "110108"/>
<Area name = "Mentougou District" id = "110109"/>
<Area name = "Fangshan District" id = "110111"/>
<Area name = "Tongzhou District" id = "110112"/>
<Area name = "Shunyi District" id = "110113"/>
<Area name = "Changping District" id = "110114"/>
<Area name = "Daxing District" id = "110115"/>
<Area name = "Huairou district" id = "110116"/>
<Area name = "Pinggu district" id = "110117"/>
</City>
<City name = "County" id = "110200">
<Area name = "Miyun county" id = "110228"/>
<Area name = "Yanqing County" id = "110229"/>
</City>
</Province>
<Province name = "Tianjin" id = "120000">
<City name = "city jurisdiction" id = "120100">
<Area name = "Heping District" id = "120101"/>
<Area name = "Hedong district" id = "120102"/>
<Area name = "Hexi District" id = "120103"/>
<Area name = "Nankai district" id = "120104"/>
<Area name = "Hebei District" id = "120105"/>
<Area name = "Hongqiao district" id = "120106"/>
<Area name = "Tanggu District" id = "120107"/>
<Area name = "hanggu district" id = "120108"/>
<Area name = "Dagang district" id = "120109"/>
<Area name = "dongli district" id = "120110"/>
<Area name = "Xiqing district" id = "120111"/>
<Area name = "Jinnan District" id = "120112"/>
<Area name = "Beichen District" id = "120113"/>
<Area name = "Wuqing district" id = "120114"/>
<Area name = "baodi district" id = "120115"/>
</City>
<City name = "County" id = "120200">
<Area name = "Ninghe county" id = "120221"/>
<Area name = "Jinghai County" id = "120223"/>
<Area name = "Ji Xian" id = "120225"/>
</City>
..........
........
........
</Province>
<Root>
<Script language = "JavaScript" type = "text/JavaScript">
VaR xmldoc;
VaR nodeindex;
Function getxmldoc ()
{
Xmldoc = new activexobject ("Microsoft. xmldom ");
VaR currnode;
Xmldoc. async = false;
Xmldoc. Load ("provincecity. xml ");
If (xmldoc. parseerror. errorcode! = 0)
{
VaR myerr = xmldoc. parseerror;
Alert ("error! "+ Myerr. Reason );
}
Getprovince1 ();
}
Function getprovince1 ()
{
VaR nodelist = xmldoc. selectsinglenode ("root"). childnodes;
VaR dropelement = Document. getelementbyid ("select1 ");
For (VAR I = 0; I <nodelist. length; I ++)
{
VaR provincenode = nodelist [I];
VaR eoption = Document. createelement ("option ");
Eoption. value = provincenode. getattribute ("ID ");
Eoption. Text = provincenode. getattribute ("name ");
Dropelement. Add (eoption );
}
}
Function selectcity1 ()
{
VaR dropelement = Document. getelementbyid ("select1 ");
VaR id = dropelement. Options [dropelement. selectedindex]. value;
VaR provincenode = xmldoc. selectsinglenode ("// root/province [@ ID =" + ID + "]");
VaR city = Document. getelementbyid ("select2 ");
VaR area = Document. getelementbyid ("select3 ");
Removedropdownlist (city );
Removedropdownlist (area );
For (VAR I = 0; I <provincenode. childnodes. length; I ++)
{
VaR citynode = provincenode. childnodes [I];
VaR eoption = Document. createelement ("option ");
Eoption. value = citynode. getattribute ("ID ");
Eoption. Text = citynode. getattribute ("name ");
City. Add (eoption );
}
}
Function selectarea1 ()
{
VaR dropelement = Document. getelementbyid ("select2 ");
VaR id = dropelement. Options [dropelement. selectedindex]. value;
VaR provincenode = xmldoc. selectsinglenode ("// root/province/City [@ ID =" + ID + "]");
VaR area = Document. getelementbyid ("select3 ");
Removedropdownlist (area );
For (VAR I = 0; I <provincenode. childnodes. length; I ++)
{
VaR citynode = provincenode. childnodes [I];
VaR eoption = Document. createelement ("option ");
Eoption. value = citynode. getattribute ("ID ");
Eoption. Text = citynode. getattribute ("name ");
Area. Add (eoption );
}
}
Function removedropdownlist (OBJ)
{
VaR Len = obj. Options. length;
// Alert (LEN );
For (VAR I = Len; I> = 0; I --)
{
OBJ. Remove (I );
}
}
</SCRIPT>
Demo: http://home.goofar.com/lkc311/XmlDropDownlist.htm
