Add text to input element (noob question)

Question

Hey all,

So I am creating a very basic app to get my feet wet (apologies in advance!) and I am a little stuck more than likely because I don't fully understand event handlers.

What I am trying to do is add an event listener so that when a button is clicked a number is added to a number input element (a calculator pretty much).

This is done by onclick send it to another method and add it to the text field. It could be a number of things I am sure but I think perhaps it is one (or both) of two things.

• In my event listener I call my addNumber method to handle the event on click and that method takes two arguments, eventInfo (which I am a little lost on) and the number to add to the text box and I think there is something wrong those arguments.
• innerText is not the proper call to add to an input element.

Thanks in advance!

Here is my code:

            args.setPromise(WinJS.UI.processAll());

            var oneButton = document.getElementById("one");
            oneButton.addEventListener("click", addNumber(eventInfo, 1), false);

        }
    };

    app.oncheckpoint = function (args) {
 args.setPromise().
    };

    
//method adds passed number to the number field
    function addNumber(eventInfo, numberToAdd) {                

            var numberField = document.getElementsById("numberInput");
            numberField.innerText = numberToAdd;
        
    }