JavaScript conditionals is how you add logic to your programming and help you make decisions with code.
For example, when we shop online and ready to pay our items, we will enter our credit card number, if our information is correct, it will match the code, and we will receive a confirmation message. If our credit card information is wrong, the code will send us an error message.
There are three JS conditional keywords: If, Else If, and Else.
How do we use those conditional keywords in JavaScript?
If
For example, if the website wants to send an message about your age is younger than 18, you can’t enter the bar.
if (age < 18) {
console.log(“Sorry, you are not old enough to enter the venue.”);
}
Else If
If your age is older than 18 but younger than 21, you can enter the bar but can not drink.
else if (age < 21) {
console.log(“You can enter, but can not drink.”);
}
Else
If your age is older than 21, feel free to drink.
else {
console.log(“Come on in. Enjoy the drink.”);
}
转载于:https://www.jianshu.com/p/cf26214b533d