let obj = {"a": 3, "b": 2, "6": "a"}

Object.keys(obj).forEach((item) => {console.log("item", obj[item])})

// a
// 3
// 2

还添加了递归方式：

function iterate(obj) {
    // watch for objects we've already iterated so we won't end in endless cycle
    // for cases like var foo = {}; foo.bar = foo; iterate(foo);
    var walked = [];
    var stack = [{obj: obj, stack: ''}];
    while(stack.length > 0)
    {
        var item = stack.pop();
        var obj = item.obj;
        for (var property in obj) {
            if (obj.hasOwnProperty(property)) {
                if (typeof obj[property] == "object") {
                  // check if we haven't iterated through the reference yet
                  var alreadyFound = false;
                  for(var i = 0; i < walked.length; i++)
                  {
                    if (walked[i] === obj[property])
                    {
                      alreadyFound = true;
                      break;
                    }
                  }
                  // new object reference
                  if (!alreadyFound)
                  {
                    walked.push(obj[property]);
                    stack.push({obj: obj[property], stack: item.stack + '.' + property});
                  }
                }
                else
                {
                    console.log(item.stack + '.' + property + "=" + obj[property]);
                }
            }
        }
    }
}

用法：

iterate({ foo: "foo", bar: { foo: "foo"} }); 

JavaScript中的对象是财产的集合，因此可以在for-each语句中循环。

您应该将obj视为键值集合。

jquery允许您立即执行以下操作：

$.each( obj, function( key, value ) {
  alert( key + ": " + value );
});

if (typeof obj === 'object' && obj !== null) {
    Object.keys(obj).forEach(key => {
        console.log("\n" + key + ": " + obj[key]);
    });
}

// *** Explanation line by line ***

// Explaining the bellow line
// It checks if obj is neither null nor undefined, which means it's safe to get its keys. 
// Otherwise it will give you a "TypeError: Cannot convert undefined or null to object" if obj is null or undefined.
// NOTE 1: You can use Object.hasOwnProperty() instead of Object.keys(obj).length
// NOTE 2: No need to check if obj is an array because it will work just fine.
// NOTE 3: No need to check if obj is a string because it will not pass the 'if typeof obj is Object' statement.
// NOTE 4: No need to check if Obj is undefined because it will not pass the 'if type obj is Object' statement either.
if (typeof obj === 'object' && obj !== null) {

    // Explaining the bellow line
    // Just like in the previous line, this returns an array with
    // all keys in obj (because if code execution got here, it means 
    // obj has keys.) 
    // Then just invoke built-in javascript forEach() to loop
    // over each key in returned array and calls a call back function 
    // on each array element (key), using ES6 arrow function (=>)
    // Or you can just use a normal function ((key) { blah blah }).
    Object.keys(obj).forEach(key => {

        // The bellow line prints out all keys with their 
        // respective value in obj.
        // key comes from the returned array in Object.keys(obj)
        // obj[key] returns the value of key in obj
        console.log("\n" + key + ": " + obj[key]);
    });
}

女孩和男孩们，我们在2019年，我们没有那么多时间打字。。。所以，让我们来做这个酷炫的新花式ECMAScript 2016：

Object.keys(obj).forEach(e => console.log(`key=${e}  value=${obj[e]}`));