修改数据显示checkbox选中问题

Array.prototype.contains = function (element) {

    for (var i = 0; i < this.length; i++) {
        if (this[i] == element) {
            return true;
        }
    }
    return false;
};
$(function(){
var arrays = cb.split(",");
$("input[type='checkbox']").each(function() {
if (arrays.contains($(this).val())) {
$(this).attr("checked", "checked");
         }
     });
});