<div class="unit-ilo-edit-modal">
  <form class="form-horizontal" ng-submit="saveILO()" role="form">
    <div class="modal-header">
      <h3>{{isNew ? "Create ILO" : "Edit ILO: " + ilo.ilo_number}}</h3>
    </div>
    <div class="modal-body">
      <div class="form-group" required>
        <label class="col-sm-3 control-label">Name</label>
        <input type="text" class="form-control col-sm-7"
        ng-model="ilo.name"/>
      </div>
      <div class="form-group" required>
        <label class="col-sm-3 control-label">Abbreviation</label>
        <input type="text" class="form-control col-sm-7"
        ng-model="ilo.abbreviation"/>
      </div>
      <div class="form-group" required>
        <label class="col-sm-3 control-label">Description</label>
        <markdown-editor class="col-sm-7" height="200" placeholder="Enter markdown description..." ng-model="ilo.description"></markdown-editor>
      </div>
    </div>
    <div class="modal-footer text-right">
      <input type="submit" class="btn btn-primary" value="{{isNew ? 'Create' : 'Update'}}" />
    </div>
  </form>
</div>

<div class="unit-ilo-edit-modal">
  <form class="form-horizontal" ng-submit="saveILO()" role="form">
    <div class="modal-header">
      <h3>{{isNew ? "Create ILO" : "Edit ILO: " + ilo.ilo_number}}</h3>
    </div>
    <div class="modal-body">
      <div class="form-group" required>
        <label class="col-sm-3 control-label">Name</label>
        <input type="text" class="form-control col-sm-7"
        ng-model="ilo.name"/>
      </div>
      <div class="form-group" required>
        <label class="col-sm-3 control-label">Abbreviation</label>
        <input type="text" class="form-control col-sm-7"
        ng-model="ilo.abbreviation"/>
      </div>
      <div class="form-group" required>
        <label class="col-sm-3 control-label">Description</label>
        <markdown-editor class="col-sm-7" height="200" placeholder="Enter markdown description..." ng-model="ilo.description"></markdown-editor>
      </div>
    </div>
    <div class="modal-footer text-right">
      <input type="submit" class="btn btn-primary" ng-disabled="ilo.name == null || ilo.abbreviation == null || ilo.description == null" value="{{isNew ? 'Create' : 'Update'}}" />
    </div>
  </form>
</div>

Add disabled button to ILO modal when invalid form
ENHANCE: Add disabled button to ILO modal when invalid form
