JS While Loop
JS While Loop
In JavaScript, a “while” loop is a control flow statement that allows you to repeatedly execute a block of code as long as a specified condition is true. Here’s the basic syntax for a while loop:
while (condition) {
// code block to be executed
}
In this loop, “condition” is an expression that will be evaluated before each iteration of the loop. If the condition is true, the code block will be executed, and then the condition will be evaluated again. This will continue until the condition becomes false, at which point the loop will terminate, and control will move to the next statement in the program.
Here’s an example of using a while loop to repeatedly prompt the user for input until they enter a valid value:
let userInput;
while (userInput !== "yes" && userInput !== "no") {
userInput = prompt("Please enter yes or no:");
}
In this code, the loop will continue to prompt the user for input until they enter either “yes” or “no”. The condition in the while loop checks whether the user’s input is not equal to “yes” and not equal to “no”. As long as this condition is true, the loop will keep executing, and the prompt will keep appearing.
It’s important to be careful when using while loops, as they can potentially lead to infinite loops if the condition is never false. To avoid this, make sure that the condition is set up correctly, and that there’s some way for the loop to eventually terminate.