var d = document;

function togg_img() {
  var f = d.frmTask;
  var img = d.getElementById('bool_img');

  if (f.send_solved_task.value == '1') {
    f.send_solved_task.value = 0;
    img.src = img.src.replace('/active.', '/nactive.');
  } else {
    f.send_solved_task.value = 1;
    img.src = img.src.replace('/nactive.', '/active.');
  }
}