JavaScript getElementById returns null

Question

I'm learning JavaScript and I'm wondering why something like: `document.getElementById('partofid'+variable+number)` doesn't work? Here are samples and JSfiddle link, I want "next" button to remove displayed item and show the next one. HTML: ```

1

next ``` JS: ``` var counter = 1; var button = document.getElementById('next'); button.addEventListener("click",function(){ var currentDiv = document.getElementById('div-'+counter); currentDiv.remove(); var nextDiv = document.getElementById('div-'+counter+1); alert(nextDiv); // why does it return null alert('div-'+counter+1); // while this doesn't? nextQuestion.style.display = "block"; counter++; },true); ```

Accepted Answer

Try using `parseInt`:

```
var nextDiv = document.getElementById('div-'+parseInt(counter+1,10));
```

The parseInt function converts its first argument to a string, parses it, and returns an integer.The second arguement is radix which is "base", as in a number system.

Demo

JavaScript getElementById returns null

Solution

Problem