How do you compare user input to values inside an array?

Question

I am wanting to create a very simple script that checks user's input to a pre-existing array. However, it doesn't seem to work and I'm not sure why. Please, keep in mind I'm new to this and trying to learn.

<script>
    var usernumber = prompt('What is your number?');
    var numbers = ['1', '2', '3'];
    if (usernumber == 'numbers') //If the user number matches one of preset numbers
    {
        alert('Match');
    } else {
        alert('No match found.');
    }
</script>

Possible duplicate of How do I check if an array includes an object in JavaScript? — cнŝdk
– cнŝdk, Commented Nov 13, 2017 at 14:37
You should explain what exactly it's doing incorrectly, versus what you want. — user3556757
– user3556757, Commented Nov 13, 2017 at 14:38
You're going to find that there are many ways to skin this cat. If you visit: developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/… You can learn about how to manipulate your array and choose the best solution for what you're attempting to do. — Chris
– Chris, Commented Nov 13, 2017 at 14:42

Taha Paksu · Accepted Answer · 2017-11-13 14:35:00Z

4

You can use Array.indexOf prototype function here:

if(numbers.indexOf(usernumber) >= 0){
    alert('Match');
}

Reference: https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/indexOf

answered Nov 13, 2017 at 14:35

Taha Paksu

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Comments

Hemant Rajpoot · Accepted Answer · 2017-11-13 14:37:26Z

1

this will work fine for you

<script>
    var usernumber = prompt('What is your number?');
    var numbers = ['1', '2', '3'];
    for(i=0;i<=numbers.length;i++)    
     {if (usernumber == numbers[i]) 

    {
        alert('Match');
         break;
    } }
     if(i==numbers.length) {
        alert('No match found.');
    }
</script>

answered Nov 13, 2017 at 14:37

Hemant Rajpoot

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Comments

UchihaItachi · Accepted Answer · 2017-11-13 14:38:17Z

1

You can check the following code

    var usernumber = prompt('What is your number?');
    var numbers = ['1', '2', '3'];
    if (numbers.indexOf(usernumber) >=0 ) //If the user number matches one of preset numbers
    {
        alert('Match');
    } else {
        alert('No match found.');
    }

answered Nov 13, 2017 at 14:38

UchihaItachi

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Comments

Ayman Ftiti · Accepted Answer · 2017-11-13 14:47:46Z

1

array.indexof(item) return -1 if the item does not exist on the array else return item's index

<script>
    var usernumber = prompt('What is your number?');
    var numbers = ['1', '2', '3'];
    if (numbers.indexOf(usernumber) >=0 ) // check if the item exists on the array
    {
        alert('Match');
    } else {
        alert('No match found.');
    }
</script>

answered Nov 13, 2017 at 14:47

Ayman Ftiti

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Comments

Erick Lanford Xenes · Accepted Answer · 2017-11-13 14:38:57Z

0

 <script>
    var usernumber = prompt('What is your number?');
    var numbers = new Array();
    numbers['1'] = true;
    numbers['2'] = true;
    numbers['3'] = true;
    if (numbers[usernumber]) //If the user number matches one of preset numbers
    {
        alert('Match');
    } else {
        alert('No match found.');
    }
</script>

answered Nov 13, 2017 at 14:38

Erick Lanford Xenes

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