1 Parent with 2 Child Drop Down

Question

I am trying to create 1 Parent Drop Down, that has 2 dependent child drop down lists using JAVASCRIPT.

My html page is at - http://www.larkgrove.com/entryform/entryform.html

I am using the Dynamic Options Lists / Dependent Selects: http://www.javascripttoolbox.com/lib/dynamicoptionlist/examples.php

If you check out my site, you can see that I can get the Child lists to change between nothing there and "NULL", but thats about all I can do.

THANKS!

Answer 1

Well, first of all, let's have a look at your code:

<script type="text/javascript">
var TESTLIST = new DynamicOptionList("PARENT1","CHILD1","CHILD2");
TESTLIST.forValue("A").forValue("A").forValue("A").addOptionsTextValue("C","C","D","D");
</script>
<select name="PARENT1">
    <option value="A">A</option>
    <option value="B">B</option>
</select>
<br /><br />
<select name="CHILD1"><script type="text/javascript">TESTLIST.printOptions("CHILD1")</script></select>
<br /><br />
<select name="CHILD2"><script type="text/javascript">TESTLIST.printOptions("CHILD2")</script></select>

I don't think that's doing what you are intending it to do, especially this:

TESTLIST.forValue("A").forValue("A").forValue("A").addOptionsTextValue("C","C","D","D");

See how you call .forvalue("A") several times redundantly? If you look at the code example you see:

regionState.forValue("west").addOptions("California","Washington","Oregon");

I would try something more like this:

TESTLIST.forValue("A").addOptionsTextValue("C","D");
TESTLIST.forValue("B").addOptionsTextValue("E","F");

Answer 2

I know you are using the Dynamic options script, but I thought that I would put up a quick from scratch solution. The code is a little verbose, but I am hoping it will be easier to see whats going on this way. The final working page is here: http://ryanscook.com/Files/DropDownListTest.htm

Lets start by assuming you have this html:

<select id="parentList" onchange="parentList_OnChange(this)">
    <option>Choose an option</option>
    <option value="A">A</option>
    <option value="B">B</option>
    <option value="C">C</option>
    <option value="D">D</option>
</select>

<select id="childList1"></select>
<select id="childList2"></select>

You will notice that we have an onchange handler, here is the java script:

// Data for child list 1, this is a of the parent value to one or more options
var childList1Data = {
    "A": ["ChildList1 - A1", "ChildList1 - A2", "ChildList1 - A3"],
    "B": ["ChildList1 - B1"],
    "C": ["ChildList1 - C1", "ChildList1 - C2"],
    "D": ["ChildList1 - D1", "ChildList1 - D2"]
};


// Data for child list 2, this is a of the parent value to one or more options
var childList2Data = {
    "A": ["ChildList2 - A1", "ChildList2 - A2"],
    "B": ["ChildList2 - B1", "ChildList2 - B2", "ChildList2 - B3"],
    "C": ["ChildList2 - C1", "ChildList2 - C2"],
    "D": ["ChildList2 - D1"]
};


// onchange is called when the parent value is changed
function parentList_OnChange(objParentList) {
    var child1 = document.getElementById("childList1");
    var child2 = document.getElementById("childList2");

    // Remove all options from both child lists
    removeOptions(child1);
    removeOptions(child2);

    // Lookup and get the array of values for child list 1, using the parents selected value
    var child1Data = childList1Data[objParentList.options[objParentList.selectedIndex].value];

    // Add the options to child list 1
    if (child1Data) {
        for (var i = 0; i < child1Data.length; i++) {
            child1.options[i] = new Option(child1Data[i], child1Data[i]);
        }
    }


    // Do the same for the second list
    var child2Data = childList2Data[objParentList.options[objParentList.selectedIndex].value];

    if (child2Data) {
        for (var i = 0; i < child2Data.length; i++) {
            child2.options[i] = new Option(child2Data[i], child2Data[i]);
        }
    }
}


function removeOptions(objSelect) {
    while (objSelect.options.length > 0)
        objSelect.options[0] = null;
}

I hope this helps and was not to far off from your question.