jsp动态下拉框的实现

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1、总是碰到两表关联时，下拉框select能以数据库中主键作为option的value属性值，以对应有意义的说明作为textNode值（option之间的值）;下面通过ajax来解决一个试用于任何以number为主键的表：js部分//-----------------------------------------------------hw.jsvar   xmlHttp;varkeyname;varvaluename;vartablename;        functioncreateXmlHttp(){            if(window.

2、XMLHttpRequest){                xmlHttp=newXMLHttpRequest();}else{               xmlHttp=newActiveXObject("Microsoft.XMLHTTP");                    }               }       functiongetKeyValue(table,key,value){          keyname=key;          valuename=value;          tablename=ta

3、ble;          createXmlHttp();          xmlHttp.open("post","SelectDynamicServlet?table="+table+"&key="+key+"&value="+value);       //   alert(keyname);          xmlHttp.onreadystatechange=getUserCallback;          xmlHttp.send(null);       //   alert(keyname);          }      

4、 functiongetUserCallback(){         if(xmlHttp.readyState==4){            if(xmlHttp.status==200){               //alert(keyname);               vartables=xmlHttp.responseXML.getElementsByTagName(tablename+"s")[0].               childNodes;//取得所有users下的节点;               varsele

5、ct=document.getElementById(keyname);            //   alert(select);               select.length=1;//每次只选择一个               select.options[0].selected=true;//假设第一个为选中状态               //下面               for(vari=0;i

6、         varoption=document.createElement("option");                  //alert(option);                  varkeyid=table.getElementsByTagName(keyname)[0].firstChild.nodeValue;                  //alert(userid);                  varvalueid=table.getElementsByTagName(valuename)[0].f

7、irstChild.nodeValue;                  option.setAttribute("value",keyid);                  option.appendChild(document.createTextNode(valueid));                  select.appendChild(option);                  }                           }            }          }  ----------------

8、-----------------servlet部分下面通过map存放的是对应数据库中主键及说明字段pack