javascript计算对象的长度

var obj = {"c1":1,"c2":2};
function countProperties(obj){
    for(var property in obj){
        if(Object.prototype.hasOwnProperty.call(obj,property){
            count++;
        })
    }
    return count;
}
var len = obj.length;
console.log(len);//结果为2

1 var obj = {"c1":1,"c2":2};
2 var arr = Object.keys(obj);
3 var len = arr.length;
4 console.log(len);//结果为2