Home > Developer > JavaScript

javascript--comparison

Source: Internet
Author: User
Tags logical operators
Developer on Alibaba Coud: Build your first app with APIs, SDKs, and tutorials on the Alibaba Cloud. Read more ＞



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

Comparison operators are used in logical statements to determine whether a variable or value is equal.

Given x=5, the following table explains the comparison operators:
Operator Description Examples
= = equals x==8 to False
= = = Congruent (value and type) x===5 to true;x=== "5" is false
! = does not equal x!=8 to True
> Greater than X>8 to False
< less than X<8 is true
>= greater than or equal to x>=8 false
<= less than or equal to X<=8 is true
How to use

You can use comparison operators to compare values in a conditional statement and then take action based on the result:

if (age<18) document.write ("Too Young");

You'll 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:
Operator Description Examples
&& (x < && y > 1) True
|| or (x==5 | | y==5) is false
! Not! (x==y) is true
Conditional operators

JavaScript also includes conditional operators that assign values to variables based on certain conditions.
Grammar

Variablename= (condition)? value1:value2

Example

Greeting= (visitor== "PRES")? " Dear president ":" Dear ";

If the value in the variable visitor is "PRES", assign a value of "Dear president" to the variable greeting, otherwise assign a value of "Dear".




<! DOCTYPE html>
<body>
<meta http-equiv= "Content-type" content= "text/html charset=utf-8"/>


<script>
function Print ()
{

var age = 15;
if (age < 18)
document.write ("Too Young");

var visitor = "PRES";
var greeting= (visitor== "PRES")? " Dear president ":" Dear ";
document.write (greeting);

}
</script>

<td><input type= "text" name= "TxtRow1" id= "Txt1" size= "+"/></td>

<button onclick= "Print ()" > click here </button>

</body>



javascript--comparison

This article is an English version of an article which is originally in the Chinese language on aliyun.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to info-contact@alibabacloud.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

Related Keywords:
javascript boolean comparison javascript canvas library comparison comparison algorithm comparison operators comparison signs comparison symbols bitwise comparison

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

What's Trending
Top 10 Tags
datastax versions naming convention zookeeper client class definition md5 microsoft sql server 2005 data structures exception handling error handling
Top 10 Keywords
microsoft download center down wordpress address url site address url wordpress address url windows installer 4 0 download 302 not found web address url definition site address url wordpress db2 integer mac os installation step by step pdf abbreviation for return

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

Get Started for Free

  • Sales Support

    1 on 1 presale consultation

    Chat Contact Sales

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

    Open a Ticket

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.

    Learn More