How can I put a button in Google map's Infowindow?

Question

I'm in a big trouble about the title. I just want to make a button inside the Infowindow, but it doesn't work at all. Oh, infact, this code is not using google map API, instead another API, but that doesn't matter. Here's my code:

    var infowindow = new daum.maps.InfoWindow({
            position: iwPosition,
            content: iwContent
        });

        infowindow.setContent(positions[i].content +
                     '<div style="float: right">' +
                        '<img id="infoCloseButton" src="img/icon/11_details window/04_details window_back_button_image.png" onclick="infowindow.close()"/>' + 
                        '<img src="img/icon/11_details window/04_details window_back_button_text.png"/>' +
                     '</div>' +
                     '<div style="float: right">' + 
                        '<img src="img/icon/11_details window/03_details window_way_button_image.png"/>' + 
                        '<img src="img/icon/11_details window/03_details window_way_button_text.png"/>' +
                     '</div>');

        daum.maps.event.addListener(marker, 'click', makeClickListener(map, marker, infowindow));

You can see that an image is going to work like a button(the first tag line), using onclick=removeIw(infowindow), and the removeIw function needs to work as a closing this infowindow. But the thing is that an error appears which is saying that removeIw is not defined. Whats the problem? Somebody help me, please...