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How to use the ternary operator in JavaScript

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Dec 21, 2018 pm 03:27 PM

ternary operator

The ternary operator in How to use the ternary operator in How to use the ternary operator in JavaScript is the only operator that uses three operators. Its usage syntax is [Conditional expression? Expression 1: Expression 2;].

How to use the ternary operator in JavaScript

The operating environment of this article: Windows 7 system, javascript version 1.8.5, Dell G3 computer.

The ternary operator is one of the operators. As the name suggests, it is the only operator that uses three operators. Due to its nature, it can be said to be a simple rewrite of the if statement. The Boolean value represents its Propositions are two values of true or false, written as true and false respectively, and are mainly used for conditional branches.

Let’s look at the specific use of the ternary operator.

Let’s first take a look at the syntax of if statements and ternary operators

How to use if conditional statements in How to use the ternary operator in How to use the ternary operator in JavaScript , we use the if statement to have three lines or more expressions

Execute expression 1 when the conditional expression is true (true), and execute expression 2 when it is false (false).

if（条件表达式）{ 
  //表达式1 
} else { 
  //表达式2 
}

However, if you use the ternary operator, you can briefly describe the same content as the above if statement in one line, as shown below.

The syntax of the ternary operator

条件表达式？表达式1：表达式2;

Let’s look at a specific example

If If the amount of money is greater than 5000 (including 5000), it means rich. If it is less than 5000, it means poor.

The if statement code is as follows

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>How to use the ternary operator in How to use the ternary operator in JavaScript</title>
</head>
<body>
<script>
var money = 10000;
if (money >= 5000) {
document.write ("富有");
} else {
document.write ("贫穷");
}
</script>
</body>
</html>

The running result is as follows

How to use the ternary operator in How to use the ternary operator in JavaScript

Next, let’s change the value of the variable money to 3000.

<script>
var money = 3000;
if (money >= 5000) {
document.write ("富有");
} else {
document.write ("贫穷");
}
</script>

The running results are as follows

How to use the ternary operator in How to use the ternary operator in JavaScript

The code using the ternary operator is as follows

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>How to use the ternary operator in How to use the ternary operator in JavaScript</title>
</head>
<body>
<script>
var money = 10000;
money > 5000 ? document.write("富有") : document.write("贫穷") ;
</script>
</body>
</html>

Due to the value of the variable money is 10000 greater than 5000, so it appears as "rich".

How to use the ternary operator in JavaScript

Next, let’s change the value of the variable money to 3000.

<script>
var money = 3000;
money > 5000 ? document.write("富有") : document.write("贫穷") ;
</script>

The running results are as follows

How to use the ternary operator in JavaScript

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