title: Knockout.js Runtime Error
body: <p>I'm trying to loop through out the list of items in a collection and compare each item if email address of item to be added on the collection already exist but I got run time error "JavaScript runtime error: Function expected". Please anyone help me what is missing with my code below?</p>
  
  <p><strong>ViewModel</strong></p>
  
  <pre><code>self.AddReceiver = function () {
          var newReceiverData = ko.toJS(self.newReceiver);
          if (ReceiverValidate()) {
              ko.utils.arrayForEach(self.receivers(), function (item) {
                  if (item.EmailAddress() == newReceiverData.receiveremailaddress) {
                      alert("Email already exist on the list");
                      return false;
                  }
              });
              self.receivers.push({
                  EmailAddress: newReceiverData.receiveremailaddress,
                  FirstName: newReceiverData.receiverfirstname,
                  LastName: newReceiverData.receiverlastname
              });
              ClearReceiverInput();
          }
      }; 
  </code></pre>
  
  <p><strong>Screenshot error</strong></p>
  
  <p><img src="https://i.stack.imgur.com/DWPTu.png" alt="enter image description here"></p>