CODEWITHSUNDEEP
javascript
jmike
jmike

Reputation: 481

How do I loop back to the prompt if answer is incorrect?

How do I loop back to the prompt question if the user enters the wrong answer and I want the question to repeat until they get the correct answer?

<html>

<head>
    <script>
    </script>
    <title> Javascript program</title>
</head>

<body>
    <script>
        var company = (prompt("What the name of the company that developed the javascript language?", ""));
        if (company == 'netscape') {
            alert("correct answer!");

        } else {
            alert("wrong answer");

        }
    </script>
</body>

</html>

Upvotes: 3

Views: 14023

Answers (6)

DanielQ
DanielQ

Reputation: 1

I hope this short function with a couple of conditions helps anyone who needs to check if a certain piece of data is a number and if it is within a given range. I used it for dates, but you can pretty much use it for any kind of date-related data.

const checkData = function (data, value1, value2) {
 let x = (+prompt(`Choose the first date's ${data}. You can choose from ${value1} to ${value2}.`));
 if ((x < value1 || x > value2) || Number.isFinite(x) === false) {
  while ((x < value1 || x > value2) || Number.isFinite(x) === false) {
   x = (+prompt(`Criteria have not been met. You must type a number between ${value1} and ${value2}`))
  }
 }
 return x;};
checkData('month', 1, 12);

Upvotes: 0

Liang
Liang

Reputation: 515

you need to include the function in itself until it meets the requirement and return(exit the function);

ask();
function ask(){
    var answer=prompt("Question..?");
    if(answer=="netscape"){
        alert("correct");
        return;
    }
    alert("wrong answer");
    ask();  
}

Upvotes: 0

S4beR
S4beR

Reputation: 1847

showing prompt continuously can be irritating and user always have option in Chrome to prevent a page from creating more dialogues. If you use a loop with while(true) and user opt to prevent dialogue out of irritation then your page can end up in a hang state. I would suggest to use a counter to ask questions for a specific number of time before assuming that answer is wrong as in below code

function askQuestion() {
    return prompt("What the name of the company that developed the javascript language?", "");
}

var counter = 0;
var correctAnswer = false;
while(!correctAnswer && counter < 10) {

    counter++;
    correctAnswer = askQuestion() === 'netscape';

    if (!correctAnswer) {
        alert("wrong");
    }
}

if (correctAnswer) {
    alert("correct");
} else {
    alert("sorry after 10 attempts answer is still wrong");
}

You can also check this plnkr link https://plnkr.co/edit/IbUFRC0HepfSHlvNqMzM?p=preview

Upvotes: 0

Nina Scholz
Nina Scholz

Reputation: 386736

You could use a while loop and loop forever until your condition is true and then use a break statement to exit the loop.

Basically, you could select loop which checks a condition first

while (condition) {
    // code
}

loop which checks a condition later

do {
    // code
} while (condition);

a solution inbetween

while (true) {
    // code
    if (condition) break;
    // code
}

or a recursive solution, like

function fn() {
    // code
    if (condition) {
        // code
        return
    }
    fn(); // call fn again
}

But I suggest to use an iterative approach until a value met a condition.

var company;

while (true) {
    company = prompt("What the name of the company that developed the javascript language?", "");
    if (company === 'netscape') {
        break;
    }
    alert("wrong answer");
}
alert("correct answer!");

Upvotes: 2

jkris
jkris

Reputation: 6561

You could use a loop like so:

let question = "What is the name of the company that developed the javascript language?",
    defaultAnswer = "stackoverflow",
    correctAnswer = "netscape";

while(prompt(question, defaultAnswer) !== correctAnswer) alert("Wrong answer")
alert("Correct answer");

Or you could use recursion, refer to Rajesh's answer.

Upvotes: 0

Rajesh
Rajesh

Reputation: 24945

You can wrap your code in a function and call self on incorrect value.

var max_count = 5;

function showConfirm() {
  var company = (prompt("What the name of the company that developed the javascript language?", ""));
  if (company == 'netscape') {
    alert("correct answer!");
  } else {
    alert("wrong answer");
    // to limit user for limited count
    if (--max_count > 0)
      showConfirm()
  }
}
showConfirm();

Upvotes: 4

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