forEach

//循环数据库结果

var a=db.col.find();

a.forEach(function(value){

      printjson(index);

})

//循环数组

var arr = ["ab","cd","ef"];

var show = function(value,index,ar){ print(ar) };

arr.forEach(show);

//value为当前元素值，index为当前元素在数组中的索引，ar为数组本⾝