how to add style in angularjs based on condition in html itself - angularjs

Question

I have the above page structure . i want to check a conditon to apply style in div with id if the buttonlayout has a class proceed.
<div>
<div id="main">
</div>
<div id='buttonlayout" class="proceed">
</div>
I am displaying the <div id='buttonlayout" class="proceed"></div> based on some conditions. so if the div doesnt exist I dont want to apply sty;e. How can I check this in angular js?
So the logic I am looking for is
if (.div-proceed) exist add an extra style to div (with id main). Is it possible to check in my html page itself (ng-class)?

Answer 1

You can set conditions in ng-class, as sample $scope.proceed default is false our condition is when $scope.proceed is true add class proceed to the element.
This mean if $scope.proceed = false the class not exist, and if it true class is exist.
var app = angular.module("app", []);
app.controller("ctrl", ["$scope", "$filter", function($scope, $filter) {
$scope.change = function() {
$scope.proceed = !$scope.proceed;
}
}]);
body {
padding-top: 50px;
}
a{cursor: pointer}
#buttonlayout {
width: 100px;
height: 100px;
transition: all 0.5s;
background-color: #ccc;
}
#buttonlayout.proceed {
width: 200px;
height: 200px;
background-color: green;
}
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="app" ng-controller="ctrl">
<a ng-click="change()">click to remove/add 'proceed' class</a>
<div id="buttonlayout" ng-class="{'proceed': proceed}"></div>
</div>