Disable an Element Using jQuery 1

Tell us what’s happening:
I am writting this code and its not working

Your code so far

  $(document).ready(function() {
    $("#target1").css("color", "red").prop("disabled" , true);

<!-- Only change code above this line. -->

<div class="container-fluid">
  <h3 class="text-primary text-center">jQuery Playground</h3>
  <div class="row">
    <div class="col-xs-6">
      <div class="well" id="left-well">
        <button class="btn btn-default target" id="target1">#target1</button>
        <button class="btn btn-default target" id="target2">#target2</button>
        <button class="btn btn-default target" id="target3">#target3</button>
    <div class="col-xs-6">
      <div class="well" id="right-well">
        <button class="btn btn-default target" id="target4">#target4</button>
        <button class="btn btn-default target" id="target5">#target5</button>
        <button class="btn btn-default target" id="target6">#target6</button>

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.90 Safari/537.36.

Link to the challenge:

A page can’t be manipulated safely until the document is “ready.” Once the page Document Object Model (DOM) is ready for JavaScript code to execute then Code included inside $( document ).ready() will run.
I did this

$(document).ready(function() {
    $("#app").css("color", "red").prop("disabled" , true);

this is the result

now I used JQuery:

$("#app").css("color", "blue").prop("disabled",  true);


I don’t know how you selected your element id I guess.