function dealNull(obj) {
for (var i in obj) {
if (null == obj[i] || 'null' == obj[i] || undefined == obj[i] || 'undefined' == obj[i] || '' == obj[i]) {
obj[i] = '--';
} else if ('object' == typeof obj[i]) {
dealNull(obj[i]);
}
}
};
obj = {ApplicationNo: "AL2017082421251060784", Project_Name: null}
dealNull(obj)