//計算對象的長度,既獲得對象屬性的個數
//方法一:通過for in遍歷對象,並通過hasOwnProperty判斷是否是對象自身可枚舉的屬性
var obj = {"name": 'yzs',"age": '18'}; var length = countProperties(obj); console.log(length); function countProperties(obj) { var count = 0; for(var property in obj) { if(Object.prototype.hasOwnProperty.call(obj,property)) { count++; } } return count; } //方法二:通過Object.keys()獲取對象可枚舉屬性所組成的數組,並通過length獲取對象長度 var obj1 = {"name": 'yzs',"age": '18',"sex": 'male'}; var arr = Object.keys(obj1); var len = arr.length; console.log(len);