Home > DeveloperSection > Forums > Get getElementById from variable using JavaScript
Tanuj Kumar

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Points:940
Posted on    August-16-2013 6:55 AM

 JavaScript JavaScript 
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Hi developers! 

I have 10 input boxs on my page.

<input type="text" id="box1">

<input type="text" id="box2">

<input type="text" id="box3">

<input type="text" id="box4">

<input type="text" id="box5">

<input type="text" id="box6">

<input type="text" id="box7">

<input type="text" id="box8">

<input type="text" id="box9">

<input type="text" id="box10">

Using JavaScript I want to be able to select the input of each, but only on request using JavaScript.

I have used the following code:

document.getElementById("box1").value

which returns the value (which I want)

However I want to be able to do something with it then request the next item then do something with that.

So I have created a dummy Variable (placed outside my function as I don't want to reset the value back to 1 each time the function is called:

var current_item = "1";

I then wanted to be able to select a item using this variable and I have used it like:

document.getElementById("box" + current_item).value

current_item = current_item + 1;

however it's not working. If I alert the current_item variable it returns undefined.

If I add the current_item variable to my function it works and does what I want it to do, but keeps resetting back to 1 (as the function is recreating the variable).

Can anyone help me out on this on how to get the next input box value ?

Thanks in advance!



shreesh chandra shukla
shreesh chandra shukla

Total Post:105

Points:735
Posted on    August-17-2013 6:27 AM

Hi!

current_item is a string and when you use the + operator, it does concatenation instead of addition.

"1" + 1

"11"

If you use var current_item = 1;, it'll be an integer and you can add it by doing +1

Also,

var current_item = "1";

current_item = current_item*1 + 1;

2

When you multiply by 1, it casts it to an int, then adds 1, which results in 2 as you would expect.

thanks


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