window.onload = function () {
        var firstCb = document.getElementById("firstCb");
        var cbs = document.getElementsByName("cb");


        //全选
        firstCb.onclick = function () {
            for (var i = 0; i <cbs.length ; i++) {
                cbs[i].checked = this.checked;
            }
        }


        document.getElementById("selectAll").onclick = function () {
            for (var i = 0; i <cbs.length ; i++) {
                cbs[i].checked = true;
            }
        }


        document.getElementById("unSelectAll").onclick = function () {
            for (var i = 0; i <cbs.length ; i++) {
                cbs[i].checked = false;
            }
        }

        document.getElementById("selectRev").onclick = function () {
            for (var i = 0; i <cbs.length ; i++) {
                if(cbs[i].checked){
                    cbs[i].checked = false;
                }else if(!cbs[i].checked){
                    cbs[i].checked = true;
                }
            }
        }

    }