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    javascript - How to create while loop with alert and prompt to avoid empty input? - Stack Overflow

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    I want to create a while loop to avoid empty input. Here's my code, I want it to loop so that the user gets the same alert and then prompt window until he/she writes a name/username. Any ideas on what I'm doing wrong and how to fix it? 

    <script type="text/javascript">
confirm("Wanna play?");
var name = prompt("What's your name?");
while (name.length == 0) {
    alert("Please enter your name!");
    prompt("What's your name?");
}
else {
    document.write("Wele to my game " + name + "!" + "<br>");
}
</script>

    I want to create a while loop to avoid empty input. Here's my code, I want it to loop so that the user gets the same alert and then prompt window until he/she writes a name/username. Any ideas on what I'm doing wrong and how to fix it? 

    <script type="text/javascript">
confirm("Wanna play?");
var name = prompt("What's your name?");
while (name.length == 0) {
    alert("Please enter your name!");
    prompt("What's your name?");
}
else {
    document.write("Wele to my game " + name + "!" + "<br>");
}
</script>
    • javascript
    • loops
    • while-loop
    Share Improve this question edited Jan 20, 2017 at 16:47 Adam Michalik 9,96513 gold badges75 silver badges107 bronze badges asked Jun 8, 2016 at 16:50 Anna BannannaAnna Bannanna 1353 silver badges10 bronze badges 0
    Add a ment  | 

    4 Answers 4

    Reset to default 4

    @Renan suggested it right. Still, if you need the current code to work, you can try this:

    <script type="text/javascript">
confirm("Wanna play?");
var name = prompt("What's your name?");
while (name.length == 0) {
    alert("Please enter your name!");
    name = prompt("What's your name?");
}
document.write("Wele to my game " + name + "!" + "<br>");
</script>

    There are some errors in your code/logic:

    1. Why is there else after while? else is used with if clause only.
    2. You are asking for the name in the while loop, but not assigning it to the name variable. If you do not assign to name, how would the name variable get updated and cause the while loop to exit?

    Never abuse prompt, alert and confirm in your pages.

    I could write a lot about this but I will just leave this image here.

    Users can easily silence your attempts to call their attention via dialogs, so any extra effort you spend on that is wasted.

    See If this does what you're looking for!

    confirm("Wanna play?");
var name = prompt("What's your name?");
while (name.length == 0) {
    name = prompt("Please, insert a name to proceed!");
}
document.write("Wele to my game " + name + "!" + "<br>");

    Use This

    var name = prompt("What's your name?");
while (name.length == 0 || name == "null" || name == null) {
    name = prompt("What's your name");
}

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