I am trying to set value of an input field that is on a webpage via Chrome extension. The value does get filled successfully, however when form is submitted, it gives error of input field being empty.

Input field code:

<input type="text" class="text-center CustomTextBox ng-pristine ng-valid ng-isolate-scope ng-not-empty ng-valid-maxlength ng-touched" autocomplete="off" min="0" maxlength="6" jcs-decimals="2" jcs-allow-null="false" jcs-decimals-hide-zero="true" ng-model="p.quantity" ng-disabled="p.OutOfStock" ng-blur="vm.QtyEntered(p)" ng-change="vm.qtyChanged(p)">

Javascript (inside inject.js of my chrome extension):

var foundinput = getElementsByTagName('input').item(0);
foundinput.value = 5.00;

Could it have anything to do with ng-change not getting triggered?

P.S. When value is entered manually, the form does submit successfully.