how to get the image id and use hiding the image using prototype js?

Question

DeCheBX = $('MyDiv').insert(new Element('input', { 'type': 'checkbox', 'id': "Img" + obj[i].Nam, 'value': obj[i].IM, 'onClick': 'SayHi(this)' })); document.body.appendChild(DeCheBX); DeImg = $('MyDiv').insert(new Element('img', { 'id': "Imgx" + obj[i].Nam, 'src': obj[i].IM })); document.body.appendChild(DeImg); } SayHi = function(x) { try {

                    if ($(x).checked == true) {