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JavaScript JavaScript Loops Working with 'for' Loops Dynamically Display HTML with a Loop

Posted by Anh Tran
Anh Tran
2,556 Points

Cannot set property 'innerHTM' of Null

When excute this code, I got the warning message in the console like this main.js:8 Uncaught TypeError: Cannot set property 'innerHTM

Here my code: const main = document.querySelector('main'); let html = '';

for (let i = 0; i <= 10; i++) { html += <div>${i + 1}</div>; }

main.innerHTML = html;

Thanks everybody

2 Answers

Cameron Childres
Cameron Childres
11,820 Points
Cameron Childres
Cameron Childres
11,820 Points

Hi Anh~

Your code is looking good, but it would be easier for us to read if you use the markdown cheatsheet that's linked below the comment box like this:

```javascript
code goes here
```

This ensures we see everything you've written such as the backticks around your template literal. Here's your code with formatting:

const main = document.querySelector('main'); 
let html = '';

for (let i = 0; i <= 10; i++) { 
  html += `<div>${i + 1}</div>`; 
}

main.innerHTML = html;

When I run this it gives me the expected result, showing numbers 1-11 on separate lines in the <main> element.

However, I'll get your same error if I link the script before the <main> element in the HTML document -- for instance, if I have the script inside the <head> tags. This is because the script runs before the <main> element is read, it can't see it, so it has no element to alter. Check to make sure this specific script is linked towards the end of your <body> element.

Joseph Yhu
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
Joseph Yhu
PHP Development Techdegree Graduate 48,638 Points
Joseph Yhu
.a{fill-rule:evenodd;}techdegree seal-36
Joseph Yhu
PHP Development Techdegree Graduate 48,638 Points

You have to surround <div>${i + 1}</div> with backticks.

Cameron Childres
Cameron Childres
11,820 Points
Cameron Childres
Cameron Childres
11,820 Points

I believe the code already includes the backticks -- that's why that segment shows the way it does in the post, it's just that the forum's markdown is using them as formatting instructions.

Anh Tran
Anh Tran
2,556 Points

I've already added backticks after someone suggests, I had changed the order of the <script> tag in the html file, put it to the end of html document and this code work fine.

Thank again everybody