You need to raise html events on the elements in order to notify the webpage that a change has occurred. The first step should be to open up the F12 Developer Tools and find the events being listened to, on the element. In the DOM Explorer, on the right-side pane, is a tab that should say Events. Select the element and the window pane should populate with any events attached to it. Then once you have an idea of the events you need to raise, you will need to try the RaiseEvent method.

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If RaiseEvent method is not working, it is recommended to try to raise the events with javascript. You would use the ExecuteScript and InvokeScript methods, in Pega Robotics, on the webpage control to raise the events artificially. ExecuteScript will inject the javascript function onto the page. Then InvokeScript will call the function. Below is an example of function that takes in an element id and raises a 'change' event on the element.

function raiseEvent(element_id) {
    var target = document.getElementById(element_id);
    var eventObject = document.createEvent("Event");
    eventObject.initEvent("change", true, false);
    target.dispatchEvent(eventObject);
}

More details can also be found on the Developer Tools in IE here -- https://msdn.microsoft.com/en-us/library/dn255008(v=vs.85).aspx#events_tab.