Edit in JSFiddle

var myApp = angular.module('myApp', []);

myApp.config(function ($logProvider) {
    $logProvider.debugEnabled(true);
});

myApp.controller('myCtrl',
    function ($scope, $log) {
        $scope.printDebugLog = function () {
            $log.debug("debugLog");
        };
    }
);

<div ng-app="myApp">
    <div ng-controller="myCtrl">
        <button ng-click="printDebugLog()">print debug log</button>
    </div>
</div>