Javascript赋值运算符

问题描述 投票:-3回答:1

下面的输出给出了两个不同的答案,这是因为运算符+和+ =。让我知道为什么会得到不同的答案。

代码1 ----------->

var persons = [
  {firstname : "Malcom", lastname: "Reynolds"},
  {firstname : "Kaylee", lastname: "Frye"},
  {firstname : "Jayne", lastname: "Cobb"}
];


function getFullName(item) {
  document.getElementById("demo").innerHTML += [item.firstname,item.lastname].join(" ");

}

persons.map(getFullName);

---结束----

代码2 ----------->

var persons = [
  {firstname : "Malcom", lastname: "Reynolds"},
  {firstname : "Kaylee", lastname: "Frye"},
  {firstname : "Jayne", lastname: "Cobb"}
];


function getFullName(item) {
  document.getElementById("demo").innerHTML = [item.firstname,item.lastname].join(" ");

}

persons.map(getFullName);

-结束---

javascript assignment-operator
1个回答
0
投票

+=运算符是简写:

element.innerHTML += value;

与:相同

element.innerHTML = element.innerHTML + value;

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