var students=[
{name: "vehicleTravelLicenseCopyBack", id: "a1"},
{name: "vehicleTravelLicenseCopyFront", id: "a2"},
{name: "idCardBack", id: "a3"},
{name: "idCardFront", id: "a4"}
] var arr=[]; for(var i=0;i<students.length;i++){ arr.push(students[i]['id']); } console.log(arr,'4555');