Changing the Color of button on Click in bootstrap

See this functional example:

$("button").click(function(){
  $("button").removeClass("active");
  $(this).addClass("active");
});
.active {
  background-color: green !important;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">
<button type="button" id="btnOUs" class="btn btn-primary" ng-click="levelOU()">Organization Unitss </button>
            <button type="button" id="btnchiefdom" class="btn btn-primary" ng-click="levelCD()">Chiefdom</button>
            <button type="button" id="btndistrict" class="btn btn-primary" ng-click="levelD()">District </button>
            <button type="button" id="btnfaciltiy" class="btn btn-primary" ng-click="levelF()">Facility </button>


Replace "btnOUS" by "btnOUs" (small s) in :

var b1 = document.getElementById("btnOUS");
_______________________________________^

Hope this helps.


Basic example :

var b1 = document.getElementById("btnOUs");

b1.onclick = function() {
  b1.style.background = "green";  
}
<link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css">
<button type="button" id="btnOUs" class="btn btn-primary" ng-click="levelOU()">Organization Units </button>