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

Introduction to js comparison and logical operators_Basic knowledge

WBOY
Release： 2016-05-16 17:40:33
Original
1620 people have browsed it

Comparison and logical operators are used to test true or false.

Comparison Operators
Comparison operators are used in logical statements to determine whether variables or values ​​are equal.

Given x=5, the following table explains the comparison operators:

运算符 描述 例子
== 等于 x==8 为 false
=== 全等（值和类型） x===5 为 true；x==="5" 为 false
!= 不等于 x!=8 为 true
> 大于 x>8 为 false
< 小于 x<8 为 true
>= 大于或等于 x>=8 为 false
<= 小于或等于 x<=8 为 true
How to use
You can use comparison operators in conditional statements to compare values ​​and then take action based on the results:

if (age<18) document.write("Too young");
You will learn more about conditional statements in the next section of this tutorial.

Logical Operators
Logical operators are used to determine the logic between variables or values.

Given x=6 and y=3, the following table explains the logical operators:

运算符 描述 例子
&& and (x < 10 && y > 1) 为 true
|| or (x==5 || y==5) 为 false
! not !(x==y) 为 true
Conditional Operators
JavaScript also includes conditional operators that assign values ​​to variables based on certain conditions.

Syntax
variablename=(condition)?value1:value2
Example
greeting=(visitor=="PRES")?"Dear President ":"Dear ";
If the variable visitor If the value is "PRES", assign the value "Dear President" to the variable greeting, otherwise assign the value "Dear".

Related labels：
comparison operator Logical Operators
source：php.cn
Previous article：Introduction to the built-in methods of array objects in JavaScript_javascript skills Next article：In-depth understanding of JavaScript function replace_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
php uses NOT operator to evaluate conditions I have 4 sales offices and once all 4 sales offices receive 20 leads, only sales office nu...
From 2024-04-02 09:57:41
0
1
301
Apply styles to variables in template literals in JavaScript make${text}bold I'm trying to apply styles to TEXT inside the backtick operator.
From 2024-03-31 12:07:37
0
1
273
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！