Javascript Array not being filled

Question

So i'm trying to self learn HTML and Jscript but i cannot figure out for the life of me what i've did wrong in this piece of code, its a drop down question list that asks the user what fruits they like, and their asking to make 9 answers, so this script is to capture those answers and store them in an array but when it breaks outside the loop the last alert does not show, so i can see the array is not actually getting filled.

I used the alerts for bug checking :)

 <script>
      function submitInfo(passed){
           var Fruit = [];
           var myForm = passed+"Form";

           //alert("here start"+" "+document.getElementById(myForm).length+" "+myForm);
           for (var i = 0; i < document.getElementById(myForm).length; i++) {
                //alert("in loop");
                var myFruit = passed+"Input"+i;
                //alert(myFruit+" "+document.getElementById(myFruit).value);

                Fruit.push(document.getElementById(myFruit).value);
                // var Fruit[i] = document.getElementById(myFruit).value;
                alert(Fruit[i]);
           }
           alert(Fruit[i]);
      }
 </script>

Thank you in advance for any help, it is appreciaed

Can you provide a sample of your HTML as well please?

Stokedout
– Stokedout

2014-08-06 09:30:20 +00:00
Commented Aug 6, 2014 at 9:30 — Stokedout
– Stokedout, Commented Aug 6, 2014 at 9:30
try to declare var Fruit = new Array()

Oki E. Rinaldi
– Oki E. Rinaldi

2014-08-06 09:32:50 +00:00
Commented Aug 6, 2014 at 9:32 — Oki E. Rinaldi
– Oki E. Rinaldi, Commented Aug 6, 2014 at 9:32
Try using link to explain things better

Srinivasan MK
– Srinivasan MK

2014-08-06 09:34:09 +00:00
Commented Aug 6, 2014 at 9:34 — Srinivasan MK
– Srinivasan MK, Commented Aug 6, 2014 at 9:34

musefan · Accepted Answer · 2014-08-06 09:43:35Z

2

The array is being populated correctly, it's just that you are not testing it correctly.

The reason is because after your loop, i will be equal to document.getElementById(myForm).length. So when you use it to access the Fruit array you are accessing an index which has not been populated. You can prove this by doing the following after the loop:

alert(i);

For example, if document.getElementById(myForm).length is say 5. Your loop will run for 0..4 but it will still increment to 5 prior to deciding to break the loop (it has to increment it so it can evaluate the condition). At this point you will have 5 items in your array (indices 0-4). Then when you call the last alert, i = 5, but Fruit[5] does not exist.

If you were to change the last alert (after the loop) to Fruit[0] it should display the first item. You could also do console.log(Fruit) and check the console for the full contents of the array.

This may help to demonstrate it better.

edited Aug 6, 2014 at 9:43

answered Aug 6, 2014 at 9:32

musefan

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2 Comments

NewbietoJedi Over a year ago

Hi thank you very much, but it still refuses to work, it wont show up the last alert it just exits after it reaches 10

musefan Over a year ago

@NewbietoJedi: Prove it. Create a JSFiddle that shows your problem in action. Maybe you have console errors? Perhaps you are trying to access an element with and id that doesn't exist? That would cause you problems

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