js模板字面量，数字

字符串插值

DOCTYPE html>
<html>
<body>

<h2>JavaScript 模板字面量h2>

<p>模板字面量允许字符串中的变量：p>

<p id="demo">p>

<p>Internet Explorer 不支持模板字面量。p>

<script>
var firstName = "John";
var lastName = "Doe";

var text = `Welcome ${firstName}, ${lastName}!`;

document.getElementById("demo").innerHTML = text;
script>

body>
html>

模板字面量

DOCTYPE html>
<html>
<body>

<h2>JavaScript 模板字面量h2>

<p>模板字面量允许字符串中的变量：p>

<p id="demo">p>

<p>Internet Explorer 不支持模板字面量。p>

<script>
let header = "Templates Literals";
let tags = ["template literals", "javascript", "es6"];

let html = `<h2>${header}</h2>`;

for (const x of tags) {
  html += `<li>${x}</li>`;
}

html += `</ul>`;
document.getElementById("demo").innerHTML = html;
script>

body>
html>

确定是否是数

DOCTYPE html>
<html>
<body>

<h1>JavaScript 数字h1>

<p>您可使用全局 JavaScript 函数 isNaN() 来确定某个值是否是数：p>

<p id="demo">p>

<script>
var x = 100 / "Apple";
document.getElementById("demo").innerHTML = isNaN(x);
script>

body>
html>

超出数字范围

DOCTYPE html>
<html>
<body>

<h1>JavaScript 数字h1>

<p>Infinity （或 -Infinity）是 JavaScript 在计算数时超出最大可能数范围时返回的值：p>

<p id="demo">p>

<script>
var myNumber = 2; 
var txt = "";
while (myNumber != Infinity) {
   myNumber = myNumber * myNumber;
   txt = txt + myNumber + "
";
}
document.getElementById("demo").innerHTML = txt;
script>

body>
html>

请不要创建数值对象。这样会拖慢执行速度。
new关键词使代码复杂化，并产生某些无法预料的结果

JSandjQuery

js模板字面量，数字

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