Display dropdown items based on each other
1) I have two descents with exactly the same values. I want dropdown 2 to display values based on selection of items of dropdown 1. So the selected index of dropdown 2 will be equal to or greater than the selected index of dropdown 1. (this code works)
but when I add another snapshot and based on its items, the other two dropdowns should behave like:
2) If I select TCD in the first dropdown and change the value of B in the second dropdown, the value should be B in the third dropdown, but if I select BCD from the first dropdown it should keep the values of the other two dropdowns from the previous selection (not should go back to A)
The first part works, but the second part has problems.
Fiddle: 1) http://jsfiddle.net/wtLm4805/2/
A script with three dropdowns: 2) http://jsfiddle.net/wtLm4805/3/
while (select2.firstChild) {
select2.removeChild(select2.firstChild);
}
for (var i = 0; i < select1.options.length; i++) {
var o = document.createElement("option");
o.value = select1.options[i].value;
o.text = select1.options[i].text;
(i < select1.selectedIndex)
? o.disabled = true
: o.disabled = false ;
select2.appendChild(o);
}
Where am I going wrong?
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Since you only have one element with a class SELECTA
and one with a class SELECTB
, they will always be undefined:
var select1 = document.getElementsByClassName("SELECTA")[1];
var select2 = document.getElementsByClassName("SELECTB")[1];
var select1 = document.getElementsByClassName("SELECTA")[2];
var select2 = document.getElementsByClassName("SELECTB")[2];
If you're trying to target parameters, you can wrap the classes on the parameters themselves, or you can reference them like this:
document.getElementsByClassName("SELECTA")[0].options[1]
Not sure why you are removing / adding items to the element SELECTB
, but is this what you are going to do?
function clickButton() {
var Type= document.getElementById('Type');
var select1= document.getElementById('SELECTA');
var select2= document.getElementById('SELECTB');
if(Type.value === 'TCD') {
for(var i = 0 ; i < select1.options.length ; i++) {
select2.options[i].disabled= i < select1.selectedIndex;
}
select2.value= select1.value;
}
else {
for(var i = 0 ; i < select2.options.length ; i++) {
select2.options[i].disabled= false;
}
}
}
<select name="Type" id="Type" onchange="clickButton()">
<option value="TCD">TCD</option>
<option value="MCD">MCD</option>
<option value="BCD">BCD</option>
</select>
<select id="SELECTA" onchange="clickButton()">
<option value="A">A</option>
<option value="B">B</option>
<option value="C">C</option>
<option value="D">D</option>
</select>
<select id="SELECTB">
<option value="A">A</option>
<option value="B">B</option>
<option value="C">C</option>
<option value="D">D</option>
</select>
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You can go somewhere along these lines
var typeValue = 'TCD'; // default initialisation
$('#Type').change(function(){
var value = $(this).val();
console.log(value);
if(value == 'TCD')
{
typeValue = 'TCD';
// change something in other selects too
}
else if(value == 'MCD')
{
typeValue = 'MCD';
}
else if(value == 'BCD')
{
$('#SELECTA').val('B');
$('#SELECTB').val('B');
typeValue = 'BCD';
}
});
$('#SELECTA').change(function(){
var value = $(this).val();
console.log(value);
if(typeValue = 'TCD')
{
$('#SELECTB').val(value);
}
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<select name="Type" id="Type" >
<option value="TCD">TCD</option>
<option value="MCD" >MCD</option>
<option value="BCD" >BCD</option>
</select>
<select id="SELECTA" class="SELECTA">
<option value="A">A</option>
<option value="B">B</option>
<option value="C">C</option>
<option value="D">D</option>
</select>
<select id="SELECTB" class="SELECTB" >
<option value="A">A</option>
<option value="B">B</option>
<option value="C">C</option>
<option value="D">D</option>
</select>
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