JS check if input is in array range

Question

I'm trying to validate input using JavaScript, what i want is to bring up an alert if the user enters something that is not included in my array.

Here is what i have so far

var validAr = ["1","2","3","4","5","6","7","8","9","10","m","M"];
//dont mind the i it's been previously declared
val =+ document.getElementById('arrow_' + i + '_1').value

alert(val);
alert(validAr.indexOf(val));

If for example in the above the user enters '5' I'll alert '5', the value of val and then -1 which means that it does not belong to the array. How do I solve this?

I think you better use regular expression for such kind of validations. here is a useful reference tech.pro/tutorial/1214/… — Strikers
– Strikers, Commented Feb 20, 2014 at 9:20

James Allardice · Accepted Answer · 2014-02-20 09:21:11Z

3

Your array contains strings but you're converting the value to a number:

val = +document.getElementById('arrow_'+i+'_1').value
//    ^ Remove this to keep the value as a string

Since Array.prototype.indexOf performs a strict equality comparison it fails to find the value in the array.

You could replace the values of your array with actual numbers, but since "m" and "M" will not convert to numbers it won't work that way (you'll end up with NaN when you try to coerce them).

answered Feb 20, 2014 at 9:21

James Allardice

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1 Comment

LefterisL Over a year ago

Yes now i understand, im converting it to number cause i need it later. Converted to string just for the validation and works fine.

rajesh kakawat · Accepted Answer · 2014-02-20 09:21:57Z

1

just convert your value in string

    alert(validAr.indexOf(val.toString()));

and also remove + from +document.getElementById('arrow_'+i+'_1').value

so your code will be

var validAr = ["1","2","3","4","5","6","7","8","9","10","m","M"];
//dont mind the i it's from a for above
val = document.getElementById('arrow_'+i+'_1').value;

alert(val);
alert(validAr.indexOf(val.toString()));

answered Feb 20, 2014 at 9:21

rajesh kakawat

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LefterisL Over a year ago

Yes, i was using the + cause i need the number of it later. That fixed it. Thank you

Anoop Joshi P · Accepted Answer · 2014-02-20 09:23:23Z

0

try

   $(document).ready(function () {
        var validAr = ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "m", "M"];

        $("#text").change(function () {
            if (jQuery.inArray($(this).val(), validAr) == -1) {
                alert("exception");
            }
        });
    });

<input type="text" id="text" />

answered Feb 20, 2014 at 9:23

Anoop Joshi P

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LefterisL Over a year ago

why not just go with < 0 ?

ojovirtual · Accepted Answer · 2014-02-20 09:24:07Z

0

As you are using jQuery you can do:

if (jQuery.inArray(val,validAr)==-1)
{
    alert('Invalid');
}

answered Feb 20, 2014 at 9:24

ojovirtual

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