var imageFiles_4g_21 = new Array();
imageFiles_4g_21['0'] = new Array ('_images/4g_Spring_Start_Up.gif', '_images/4g_Spring_Start_UpMouseover.gif');

function image_on_4g_21 (position) {
   var doc = eval("document.image4g_21" + position);
   doc.src = imageFiles_4g_21[position][1];
}

function image_off_4g_21 (position) {
   var doc = eval("document.image4g_21" + position);
   doc.src = imageFiles_4g_21[position][0];
}