【JavaScript】Checkbox全選、反選、取消全選

function changeSelect(fobj1,isChecked) {
   var chk = document.getElementsByName(fobj1);
   for (var i=0;i<chk.length; i++){
 if(chk[i].checked){
    chk[i].checked = false;
 }else{
    chk[i].checked = true;
 }
   }
}




var check=true;
function changeSelect(fobj1,isChecked) {
   check = !isChecked;
   var chk = document.getElementsByName(fobj1);
   for (var i=0; i<chk.length; i++){
       if(chk[i].type='checkbox'){
   chk[i].checked = isChecked;
       }
   }
}