简体中文(ZH-CN) English(EN) 繁体中文(ZH-TW) 日本語(JA) 한국어(KO) Melayu(MS) Français(FR) Deutsch(DE)
Home > Web Front-end > JS Tutorial > body text

Basic use of Boolean objects in JavaScript programming_Basic knowledge

WBOY
Release： 2016-05-16 15:35:05
Original
1376 people have browsed it

Boolean objects are used to convert non-Boolean values ​​into Boolean values ​​(true or false).

Check Boolean value
Checks whether a boolean object is true or false.
Source code example:

<!DOCTYPE html>
<html>
<body>
&#8203;
<script>
var b1=new Boolean(0);
var b2=new Boolean(1);
var b3=new Boolean("");
var b4=new Boolean(null);
var b5=new Boolean(NaN);
var b6=new Boolean("false");
&#8203;
document.write("0 is boolean "+ b1 +"<br>");
document.write("1 is boolean "+ b2 +"<br>");
document.write("An empty string is boolean "+ b3 + "<br>");
document.write("null is boolean "+ b4+ "<br>");
document.write("NaN is boolean "+ b5 +"<br>");
document.write("The string 'false' is boolean "+ b6 +"<br>");
</script>
&#8203;
</body>
</html>
Copy after login

Test results:

0 is boolean false
1 is boolean true
An empty string is boolean false
null is boolean false
NaN is boolean false
The string 'false' is boolean true
Copy after login

Create Boolean object
Boolean object represents two values: "true" or "false"
The following code defines a Boolean object named myBoolean: 

var myBoolean=new Boolean();
Copy after login

If the Boolean object has no initial value or its value is:

0
-0
null
""
false
undefined
NaN
Copy after login

Then the value of the object is false. Otherwise, its value is true (even when the argument is the string "false")!

Related labels：
javascript
source：php.cn
Previous article：Realize beautiful page transition animation effect based on javascript with source code download_javascript skills Next article：Page custom scroll bar effect implemented by JS_javascript skills
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Latest Articles by Author
Latest Issues
Stream data from OpenAI's API using AJAX, PHP, and server-sent events How can I use Server Sent Events (SSE) to stream data from the above API to a browser clie...
From 2023-11-11 12:03:23
0
1
497
Uncaught TypeError: Cannot set property of undefined (set 'innerHTML') I'm trying to create a webpage using php, on an element of class "Continuous TextBox&...
From 2023-11-08 21:06:09
0
1
278
How to get the RGB value of CSS/HTML named color in JavaScript I have created a Javascript object called [name-rgb]. Your basic:namedColors={AliceBlue:[2...
From 2023-11-06 09:05:50
0
2
210
Why do so many JavaScript scripts append random numbers to things? collision? I've been learning JavaScript lately and have seen many examples of using Math.rand() to a...
From 2023-11-04 20:00:04
0
2
296
Identify performance limitations in JavaScript I'm trying to find the bottleneck in my Javascript. Basically I'm developing a chrome exte...
From 2023-10-31 20:47:17
0
1
229
Related Topics
More>
Popular Recommendations
Popular Tutorials
More>
Related Tutorials
Popular Recommendations
Latest courses
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template
About us Disclaimer Sitemap
php.cn：Public welfare online PHP training，Help PHP learners grow quickly！