that_it_guy
asked on
Javascript to add options to a select tag
I have a page with 2 drop down boxes on it. The second one is filled with options after a selection in the first one is made. That part is working. It will be changed to read items from a database instead of static test options, but that's not a problem. What I need to know is how do you set the value attribute of an option tag being added through javascript? If you look at the attached code, you can see the options are loaded from xml that is sent to the page. The xml elements I am loading (for this test) are named < employee > and have an id attribute. I want that id attribute set as the value of the option when loading the dropdown, so the employee name is the text you select and the employee ID is what is submitted with the form. I tried setting o.value before the mySelect.add line, but that was submitting undefined for the select. Not sure how to do this. Thanks for the help!
index.html contains:
<html>
<head>
<script language="javascript">
var xhttp;
function onSelectionChange(){
var mySelect = document.forms[0].portfolio;
if (mySelect.selectedIndex>-1){
//instantiate XmlHttpRequest
// Checking if IE-specific document.all collection exists
// to see if we are running in IE
if (document.all) {
xhttp = new ActiveXObject("Msxml2.XMLHTTP");
} else {
// Mozilla - based browser
xhttp = new XMLHttpRequest();
}
//hook the event handler
xhttp.onreadystatechange = HandlerOnReadyStateChange;
//prepare the call, http method=GET, true=asynchronous call
xhttp.open("GET",
"http://localhost/category_test/getcats.aspx?portfolio=" +
mySelect.selectedIndex, true);
//finally send the call
xhttp.send();
}
}
function HandlerOnReadyStateChange(){
var mySelect = document.forms[0].analyst;
// This handler is called 4 times for each
// state change of xmlhttp
// States are: 0 uninitialized
// 1 loading
// 2 loaded
// 3 interactive
// 4 complete
if (xhttp.readyState==4){
mySelect.innerHTML = "";
//responseXML contains an XMLDOM object
var nodes = xhttp.responseXML.selectNodes("//employee");
for (var i=0; i<nodes.length; i++){
var o = new Option();
o.text = nodes(i).text;
mySelect.add(o);
}
}
}
</script>
</head>
<body>
<form id="form1" name="form1" action="showresults.aspx">
<table>
<tr>
<td>Portfolio size:</td>
<td>
<select id="portfolio" name="portfolio"
onchange="onSelectionChange();">
<option></option>
<option>0 .. 10,000</option>
<option>10,000 to 100,000</option>
<option>Over 100,000</option>
</select>
</td>
</tr>
<tr>
<td>Authorized financial analyst:</td>
<td>
<select id="analyst" name="analyst">
</select>
</td>
</tr>
<tr>
<td>Comments</td>
<td>
<textarea name="comments" rows="3" cols="20"
ID=Textarea1></textarea>
</td>
</tr>
</table>
<input type=submit>
</form>
</body>
</html>
getcats.aspx contains only:
<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="getcats.aspx.vb" Inherits="HTUSearch.getcats" %>
getcats.aspx.vb contains:
Imports System.IO
Imports System.Xml
Partial Public Class getcats
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim xmlWriter As XmlTextWriter
Response.Clear()
Response.ContentEncoding = Encoding.UTF8
Response.ContentType = "text/xml"
Using tw As TextWriter = New StreamWriter(Response.OutputStream, Encoding.UTF8)
xmlWriter = New XmlTextWriter(tw)
xmlWriter.WriteStartDocument()
xmlWriter.WriteStartElement("employees", "employees", "")
xmlWriter.WriteStartElement("employee", "employee", "")
xmlWriter.WriteAttributeString("id", "", "1")
xmlWriter.WriteValue("Test 1")
xmlWriter.WriteEndElement()
xmlWriter.WriteStartElement("employee", "employee", "")
xmlWriter.WriteAttributeString("id", "", "2")
xmlWriter.WriteValue("Test 2")
xmlWriter.WriteEndElement()
xmlWriter.WriteEndElement()
xmlWriter.WriteEndDocument()
End Using
xmlWriter.Close()
End Sub
End Class
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ASKER
Nevermind, I figured it out. I changed the line to:
var o = new Option(nodes(i).text, nodes(i).attributes.item(0 ).value); // new Option(text, value)
Thankyou for pointing me in the right direction on adding the value to the option!
var o = new Option(nodes(i).text, nodes(i).attributes.item(0
Thankyou for pointing me in the right direction on adding the value to the option!
ASKER
Very helpful
ASKER