CODEWITHSUNDEEP
javascript
Nate E.
Nate E.

Reputation: 134

If user "cancels" prompt box then

I have tried adding a Do/While loop, then I tried a If statement but I can't seem to get this to work.

I am trying to determine if the user hasn't made three guesses, and hits cancel on the userGuess prompt .. it would then return a alert("You are a chicken");

//declare variables
var sportsArray = new Array("Football", "Basketball", "Rollerblading", "Hiking", "Biking", "Swimming");
var name = "";
var score = 0;
var loops = 0;


// prompts for user name, checks for input.
do {
    name = prompt("Enter your first name", "");
}
while (name == "");


for (loops = 1;loops <=3; loops++) {

    var sGuess = prompt("Enter a sport guess", "");
    // uses substrings to ultimately capitalize the 1st letter, and make everything after it lowerCase.
    var sFirstPart = sGuess.substr(0, 1);
    var sFirstCap = sFirstPart.toUpperCase();
    var sSecondPart = sGuess.substring(1, sGuess.length);
    var sSecondLow = sSecondPart.toLowerCase();
    // concats the two parts into one string
    var usableGuess = sFirstCap + sSecondLow;

    // if user hits cancel on the sGuess prompt
    if (sGuess == "") { 
        alert("You are a chicken");
    }

    // checks if usableGuess is contained in the arry or not.
    if (sportsArray.indexOf(usableGuess) === -1) { 
            document.write("Sorry! Try again.<br />");
            score = score -5;
        } 

        else { 
            document.write("You are good, try again.<br />"); 
            score = score + 5;
            }
    }
    //depending on the user score, prompts one of three messages.
    if (score < 0) { 
        document.write(name + ", you do not demonstrate ESP tendencies at this time.<br />");
        } else if (score < 15) { 
            document.write(name + ", you are not bad.<br />");
            } else { 
                document.write("<br/>" + name + ", you are a mind reader!<br />");
            }

Upvotes: 0

Views: 843

Answers (5)

Nate E.
Nate E.

Reputation: 134

I ended up going with the following and it does the job, in this particular case. 

    // if user hits cancel on the sGuess prompt
    if (!sGuess && loops < 4) { 
        alert("You are a chicken");
    }

Upvotes: 0

Andriy Ivaneyko
Andriy Ivaneyko

Reputation: 22061

Update sGuess checking from: 

if (sGuess == "") { 
        alert("You are a chicken");
}

to next one:

if (sGuess == null) { 
        alert("You are a chicken");
}

If user click cancel sGuess would be equal to null, to verify third user tries was ended with cancel pressing add checking for loops counter value (sGuess == null && loops == 3).

Upvotes: 1

Michael Hong
Michael Hong

Reputation: 63

"prompt" is returning null if the user hits cancel. In this case all your substr and subsequent code will fail.

    var sGuess = prompt("Enter a sport guess", "");
    if(sGuess !== null) {
        // uses substrings to ultimately capitalize the 1st letter, and make everything after it lowerCase.
        var sFirstPart = sGuess.substr(0, 1);
        var sFirstCap = sFirstPart.toUpperCase();
        var sSecondPart = sGuess.substring(1, sGuess.length);
        var sSecondLow = sSecondPart.toLowerCase();
        // concats the two parts into one string
        var usableGuess = sFirstCap + sSecondLow;

    } else {
        // if user hits cancel on the sGuess prompt
        alert("You are a chicken");
    }

...

Upvotes: 0

Scott Marcus
Scott Marcus

Reputation: 65853

Just check the result to see if there was a value supplied:

 name = prompt("Enter your first name", "");

 // If no name value was received:
 if(!name){
      alert("Chicken!");
 }

Upvotes: 0

Arun P Johny
Arun P Johny

Reputation: 388436

The prompt return s a null value where clicked on cancel, so your substring() method fails with an error(Uncaught TypeError: Cannot read property 'substr' of null).

You need to check it as soon as the prompt is called, then continue like

  var sGuess = prompt("Enter a sport guess", "");
  if (sGuess == "") {
    alert("You are a chicken");
    continue;
  }

Upvotes: 2

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