javascript遍历json对象的key和任意js对象属性

使用 keys 方法获取该对象的属性和方法:

 function Pasta(grain, width, shape) {
                this.grain = grain;
                this.width = width;
                this.shape = shape;
                this.toString = function () {
                    return (this.grain + ", " + this.width + ", " + this.shape);
                }
            }

            var spaghetti = new Pasta("wheat", 0.2, "circle");
            var arr = Object.keys(spaghetti);
            document.write(arr);

结果图:

显示 Pasta 对象中以字母“g”开头的所有可枚举属性的名称:

 function Pasta(grain, width, shape) {
                this.grain = grain;
                this.width = width;
                this.shape = shape;
            }

            function CheckKey(value) {
                var firstChar = value.substr(0, 1);
                if (firstChar.toLowerCase() == "g") {
                    return true;
                } else {
                    return false;
                }
            }

            var polenta = new Pasta("corn", 1, "mush");
            var keys = Object.keys(polenta).filter(CheckKey);
            document.write(keys);

结果如图:

遍历json对象的键:

  var an_obj = { 100: 'a', 2: 'b', 7: 'c', "name": "wu", "interesting": "Game" };
  document.write(Object.keys(an_obj));

结果如图: