JavaScript/jQuery: Divs not changing background color on loop

Question

I'm currently working on an application where I call data from an API to see how much progress a student as made in an online journal. I'm using jQuery to create a table for each student to show their progress--basically, if the student has completed a certain page, there will be a element whose background color will now be green.

Here's an example of the type of API i'm working with:

[
{ "userId": 101,
  "name": "Student1",
  "lastPageCompleted": 5 },
{ "userId": 102,
  "name": "Student2",
  "lastPageCompleted": 3 },
{ "userId": 103,
  "name": "Student3",
  "lastPageCompleted": 4 }
]

Here is the code I'm currently working with:

function getHighestPageCompleted() {
    $.ajax({
        url: "www.exampleapi.com/studentProgress",
        dataType: "json"
    }).done(function(data) {

        for (let i=0; i < data.length; i++) {
            let name = data[i].name;
            let lastPageCompleted = data[i].lastPageCompleted;
            let userId = data[i].userId;

            //here, the function loops through and creates tables with ids that match the userId, and td that haves classes of page1, page2, page3, page4, and page5
            let studentDashboard = ('<table id="' + userId + '"><tbody><tr><th>' + name + '</th><td class=\'page1\'></td><td class=\'page2\'></td><td class=\'page3\'></td><td class=\'page4\'></td><td class=\'page5\'></td></tr></table>');

            //in a separate HTML file, a class called 'dashboardContainer' receives the studentDashboards
            $(".dashboardContainer").append(studentDashboard);

            //here's the part that is tricking me up -- I need to change the background color of each td according to how many pages they've finished
            //this function is supposed to loop through each newly created table and color the background of each finished page div to green
            for (let k=0; k < lastPageCompleted; k++) {
                $("#" + userId + ".page" + k).css("background-color", "green");
            }
        }
    })
}

Can anyone provide any pointers or suggestions as to why this wouldn't work? I should point out that when I try the following in Google Chrome, it actually does work. It just doesn't work in the function.

$("#" + userId + ".page" + k).css("background-color", "green");

Answer 1

use this:

$("#" + userId + " .page" + k).css("background-color", "green"); in jquery selector class names start with dot(.) and also you must use space between parent id and child class name to distinct them.