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XML Volume Practical Tips (4): Menu Linkage

黄舟Original: 2017-02-10 16:18:331483browse

Motivation:
Now let's do a small example of applying XML in IE: solving the linkage problem of double drop-down menus. Perhaps the most common example is to select a province and then change the city options, so let's try to use XML to complete it.

I have implemented some of the functions introduced before directly using XML+XSL files. You may not be very familiar with its usage, so I will use HMTL+XML this time, hoping to make everyone more familiar with it. Clear understanding - "XML can be so simple!":)

Materials:
XML Volume Select Menu Linkage
There are 2 files: Citys.xml and CitySelect.htm

Function:
After selecting a province, the corresponding city can be automatically displayed, which is convenient for users, effectively improves data interaction, and makes your page more colorful.
Effect:
Browse here
Code:

Citys.xml 
<?xml version="1.0" encoding="gb2312"?>
<China>
  <State id="1" name="江西">
    <City>九江</City>
    <City>南昌</City>
    <City>庐山</City>
    <City>景德镇</City>
  </State>
  <State id="2" name="北京">
    <City>北京西</City>
    <City>居庸关</City>
    <City>清华园</City>
    <City>周口店</City>
  </State>
  <State id="3" name="福建">
    <City>福州</City>
    <City>厦门</City>
    <City>漳州</City>
  </State>
  <State id="4" name="甘肃">
    <City>兰州</City>
    <City>洛门</City>
    <City>嘉峪关</City>
  </State>
  <State id="5" name="广东">
    <City>广州</City>
    <City>深圳</City>
    <City>东莞</City>
    <City>石牌</City>
  </State>
  <State id="6" name="安徽">
    <City>合肥</City>
    <City>黄山</City>
    <City>九龙岗</City>
    <City>马鞍山</City>
  </State>
</China>

CitySelect.htm

Custom function: ChooseState
(Read the province in XML data name and added to SelState's drop-down list)

function ChooseState()
{
  var source;
  var sourceName = "Citys.xml";
  var source = new ActiveXObject(&#39;Microsoft.XMLDOM&#39;);   //创建一个 MSXML解析器实例
  source.async = false;
  source.load(sourceName);   //装入XML文档
  root = source.documentElement;   //设置文档元素为根节点元素
  sortField=root.selectNodes("//@name");   //搜索属性中含有name的所有节点
  for(var i=0;i<sortField.length;++i)   //增加省份名称到下拉列表
  {
    var oOption = document.createElement(&#39;OPTION&#39;);
    oOption.text = " "+sortField[i].text+" ";
    oOption.value = sortField[i].text;
     form1.SelState.options.add(oOption); 
  }
   ChooseCity();
}

Custom function: ChooseCity
(Read the corresponding city in the XML data based on the currently selected province name name and added to SelCity's drop-down list)

function ChooseCity()
{
  x=form1.SelState.selectedIndex;   //读取省份下拉框的当前选项
  y=form1.SelState.options[x].value;
  sortField=root.selectNodes("//State[@name=&#39;"+y+"&#39;]/City&q uot;);   //搜索name属性值等于
参数y的State节点下的所有city节点
  for(var i=form1.SelCity.options.length-1;i>=0;--i)   //撤消原来的列表项
  {
    form1.SelCity.options.remove(i)
  }
  for(var i=0;i<sortField.length;++i)   //增加城市名称到下拉列表
  {
    var oOption = document.createElement(&#39;OPTION&#39;);
    oOption.text = " "+sortField[i].text+" ";
    oOption.value = sortField[i].text;
    form1.SelCity.options.add(oOption); 
  }
}

Form source code

<BODY onLoad="ChooseState()">
<FORM action="" method="post" id="form1" name="form1">
<SELECT name="SelState" id="SelState" onchange="ChooseCity()" >
</SELECT>
<SELECT name="SelCity" id="SelCity" >
</SELECT>
</FORM>
</BODY>

Postscript:
Just started learning When it comes to XML, I also have the same confusion as everyone else - "I have learned XML, but how should I use this XML?" This problem has hindered me for a long, long time...

Because e-commerce and software development are my expertise, I thought it would be better to start with what I am most familiar with. So I implemented some of the most commonly used functions in website construction in XML. You can do it too!
The above is the practical tips for XML volume (4): menu linkage content. For more related content, please pay attention to the PHP Chinese website (www.php.cn)!

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