显示 JavaScript 对象将输出 [object Object]。
const person = {
name: "John",
age: 30,
city: "New York"
};
document.getElementById("demo").innerHTML = person;
自己尝试一下 →
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript Objects</h2>
<p>Displaying a JavaScript object will output [object Object]:</p>
<p id="demo"></p>
<script>
const person = {
name: "John",
age: 30,
city: "New York"
};
document.getElementById("demo").innerHTML = person;
</script>
</body>
</html>
显示 JavaScript 对象的一些常见解决方案是:
对象的属性可以显示为字符串:
const person = {
name: "John",
age: 30,
city: "New York"
};
document.getElementById("demo").innerHTML =
person.name + "," + person.age + "," + person.city;
自己尝试一下 →
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript Objects</h2>
<p>Display object properties:</p>
<p id="demo"></p>
<script>
const person = {
name: "John",
age: 30,
city: "New York"
};
document.getElementById("demo").innerHTML = person.name + ", " + person.age + ", " + person.city;
</script>
</body>
</html>
可以在循环中收集对象的属性:
const person = {
name: "John",
age: 30,
city: "New York"
};
let txt = "";
for (let x in person) {
txt += person[x] + " ";
};
document.getElementById("demo").innerHTML = txt;
自己尝试一下 →
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript Objects</h2>
<p>Display object properties:</p>
<p id="demo"></p>
<script>
const person = {
name: "John",
age: 30,
city: "New York"
};
let txt = "";
for (let x in person) {
txt += person[x] + " ";
};
document.getElementById("demo").innerHTML = txt;
</script>
</body>
</html>
您必须在循环中使用 person[x]。
person.x 将不起作用(因为 x 是一个变量)。
任何 JavaScript 对象都可以使用 Object.values()
转换为数组:
const person = {
name: "John",
age: 30,
city: "New York"
};
const myArray = Object.values(person);
myArray
现在是一个 JavaScript 数组,可以显示了:
const person = {
name: "John",
age: 30,
city: "New York"
};
const myArray = Object.values(person);
document.getElementById("demo").innerHTML = myArray;
自己尝试一下 →
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript Objects</h2>
<p>Object.values() converts an object to an array.</p>
<p id="demo"></p>
<script>
const person = {
name: "John",
age: 30,
city: "New York"
};
document.getElementById("demo").innerHTML = Object.values(person);
</script>
</body>
</html>
自 2016 年以来,所有主要浏览器都支持 Object.values()
。
54 (2016) | 14 (2016) | 47 (2016) | 10 (2016) | 41 (2016) |
任何 JavaScript 对象都可以使用 JavaScript 函数进行字符串化(转换为字符串) JSON.stringify()
:
const person = {
name: "John",
age: 30,
city: "New York"
};
let myString = JSON.stringify(person);
myString
现在是一个 JavaScript 字符串,可以显示了:
const person = {
name: "John",
age: 30,
city: "New York"
};
let myString = JSON.stringify(person);
document.getElementById("demo").innerHTML = myString;
自己尝试一下 →
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript Objects</h2>
<p>Display properties in JSON format:</p>
<p id="demo"></p>
<script>
const person = {
name: "John",
age: 30,
city: "New York"
};
document.getElementById("demo").innerHTML = JSON.stringify(person);
</script>
</body>
</html>
结果将是一个遵循 JSON 表示法的字符串:
{"name":"约翰","age":50,"city":"纽约"}
JSON.stringify()
包含在 JavaScript 中,并在所有主要浏览器中受支持。
JSON.stringify
将日期转换为字符串:
const person = {
name: "John",
today: new Date()
};
let myString = JSON.stringify(person);
document.getElementById("demo").innerHTML = myString;
自己尝试一下 →
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript Objects</h2>
<p>JSON.stringify will convert dates into strings:</p>
<p id="demo"></p>
<script>
var person = {
name: "John",
today: new Date()
};
document.getElementById("demo").innerHTML = JSON.stringify(person);
</script>
</body>
</html>
JSON.stringify
不会对函数进行字符串化:
const person = {
name: "John",
age: function () {return 30;}
};
let myString = JSON.stringify(person);
document.getElementById("demo").innerHTML = myString;
自己尝试一下 →
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript Objects</h2>
<p>JSON.stringify will not stringify functions:</p>
<p id="demo"></p>
<script>
const person = {
name: "John",
age: function () {return 30;}
};
document.getElementById("demo").innerHTML = JSON.stringify(person);
</script>
</body>
</html>
如果您在字符串化之前将函数转换为字符串,则可以“修复”此问题。
const person = {
name: "John",
age: function () {return 30;}
};
person.age = person.age.toString();
let myString = JSON.stringify(person);
document.getElementById("demo").innerHTML = myString;
自己尝试一下 →
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript Display Objects</h2>
<p>JSON.stringify will not stringify functions.</p>
<p>You have to convert functions to strings first:</p>
<p id="demo"></p>
<script>
const person = {
name: "John",
age: function () {return 30;}
};
person.age = person.age.toString();
document.getElementById("demo").innerHTML = JSON.stringify(person);
</script>
</body>
</html>
也可以对 JavaScript 数组进行字符串化:
const arr = ["John", "Peter", "Sally", "Jane"];
let myString = JSON.stringify(arr);
document.getElementById("demo").innerHTML = myString;
自己尝试一下 →
<!DOCTYPE html>
<html>
<body>
<h1>JavaScript Arrays</h1>
<p>JSON.stringify can stringify arrays:</p>
<p id="demo"></p>
<script>
const arr = ["John", "Peter", "Sally", "Jane"];
document.getElementById("demo").innerHTML = JSON.stringify(arr);
</script>
</body>
</html>
结果将是一个遵循 JSON 表示法的字符串:
[“约翰”、“彼得”、“莎莉”、“简”]