How to get two fields on your thingspeak using Jquery?

Question

I am struggling to get two fields on one URL parameter using thingspeak REST API. I have the following that attempts to do such, but im bit stuck in the middle. The idea is i have 3 checkboxs, each of them so far is doing is allowing and downloading that specific field. I want a way where if i do the checking on my if statement from those checkboxs, it should allow me to download those fields as being 2 only on my CSV file. Here is my code for the checkbox in both HTML and Jquery.

 

<div class = "custom-control custom-checkbox">

<input type = "checkbox" class="custom-control-input" id="illuminance">

<label class = "custom-control-label" for = "illuminance">Illuminance</label>

</div>

<div class ="custom-control custom-checkbox">

<input type ="checkbox" class="custom-control-input" id="button-state">

<label class ="custom-control-label" for = "button-state">Button-State</label>

</div>

<!---Downloading File using

Jquery with Buttons---->

<div class="form-group"><br>

<div class="col-md-1.9 text-center">

<button id="download" name="download" class="btn btn-warning">Download</button><br>

</div><br>

// checking for per number of entries to read.

$(function() {

$("#download").click(function(e) {

e.preventDefault();

if($('#temperature').is(':checked')) {

window.open('https://api.thingspeak.com/channels/899906/fields/1.csv');

}

if($('#illuminance').is(':checked')){

window.open('https://api.thingspeak.com/channels/899906/fields/2.csv');

}

if($('#button-state').is(':checked')){

window.open('https://api.thingspeak.com/channels/899906/fields/8.csv');

}

});

});

// checking for either of fields.

$(function() {

$("#download").click(function(e){

e.preventDefault();

});

});