Decision making in Javascript
Table of Content:
Decision making in JavaScript is done using conditional statements. The most commonly used conditional statements in JavaScript are the if
statement, the else if
statement, and the else
statement. These statements allow you to specify different code blocks to execute based on different conditions.
Conditions - If, Else, Else If
Syntax:
if (condition 1) { Execute code if condition 1 is true } else if (condition 2) { Execute code if condition 2 is true } else { Execute code if both conditions are false }
Conditions - Switch
Syntax:
switch(expression) { case 1: code to execute break; case 2: code to execute break; case 3: code to execute break; default: code to execute }
Here's an example of an if
statement in JavaScript:
var num = 10; if (num > 0) { console.log("The number is positive."); }
In this example, the if
statement checks whether the value of num
is greater than 0. If the condition is true, the code block inside the if
statement is executed, which prints the message "The number is positive." to the console.
Here's an example of an if...else
statement in JavaScript:
var num = -5; if (num > 0) { console.log("The number is positive."); } else { console.log("The number is not positive."); }
In this example, the if
statement checks whether the value of num
is greater than 0. If the condition is true, the code block inside the if
statement is executed, which prints the message "The number is positive." to the console. If the condition is false, the code block inside the else
statement is executed, which prints the message "The number is not positive." to the console.
Here's an example of an if...else if...else
statement in JavaScript:
var num = 0; if (num > 0) { console.log("The number is positive."); } else if (num < 0) { console.log("The number is negative."); } else { console.log("The number is zero."); }
In this example, the if
statement checks whether the value of num
is greater than 0. If the condition is true, the code block inside the if
statement is executed, which prints the message "The number is positive." to the console. If the condition is false, the else if
statement checks whether the value of num
is less than 0. If the condition is true, the code block inside the else if
statement is executed, which prints the message "The number is negative." to the console. If both conditions are false, the code block inside the else
statement is executed, which prints the message "The number is zero." to the console.
There are also other types of conditional statements in JavaScript, such as the switch
statement and the ternary operator (?:
). However, the if
statement and its variants are the most commonly used ones.