全部选择和全部取消多选框

function checkTrueOrFalse(obj,objname) {
    var checkBoxAll = document.getElementsByName(objname);
    for ( var i = 0; i < checkBoxAll.length; i++) {
        if(!checkBoxAll[i].disabled){
            if (obj.checked) {
                checkBoxAll[i].checked = true;
            } else {
                checkBoxAll[i].checked = false;
            }
        }
    }
}