Javascript achieves level-2 Interaction

<Form name = form1>
<Select name = province onchange = "cityname (this. selectedindex)">
<Option value = ""> select a province name </option>
</SELECT>

<Select name = city>
<Option value = ""> select a city name </option>
</SELECT>
</Form>

<Script language = JavaScript>

VaR provincename = ["Zhejiang", "Jiangsu", "Anhui", "Jiangxi"];
VaR city1 = ["Hangzhou", "Ningbo", "WenZhou", "Shaoxing", "Jinhua", "Huzhou"];
VaR city2 = ["Nanjing", "Suzhou", "Wuxi", "Changzhou", "Zhenjiang", "Xuzhou"];
VaR city3 = ["Hefei", "PiXian", "Huangshan", "Qimen", "Xiuning"];
VaR city4 = ["Nanchang", "Jiujiang", "Ganzhou", "Shangrao", "Xinyu", "Jingdezhen"];

Function province ()
{

VaR E = Document. form1.province;
For (VAR I = 0; I <provincename. length; I ++)
E. Options. Add (New Option (provincename [I], provincename [I]);
}
Function cityname (N)
{
VaR E = Document. form1.city;
E. Options. Length = 1;
If (n = 0) return;
VaR A = eval ("city" + n); // obtain the array name of the city.
For (VAR I = 0; I <A. length; I ++) E. Options. Add (New Option (a [I], a [I]);
}
Window. attachevent ("onLoad", province); // assign content to the provincial name drop-down box at the beginning
</SCRIPT>