Question: So I found this effect and I'm trying to modify it to be loaded inside a DIV `myeffect`, for example:

```
<html>
    <head></head>
    <body>
        <div class="myeffect"></div>
    </body>
</html>

```

I tried changing some variables but I'm not a JavaScript expert and I can't get it to work inside a DIC. The effect covers the whole screen from top to bottom.

The code is on Codepen and can be found here: <https://codepen.io/emilykarp/pen/bVqxRm>

Help is welcome.

Answer: 
From what I could see you were missing 3 things in your codepen.

1. you were applying the change to 'html' not '.myeffect'

In your js:

```
`var width = parseInt($('.myeffect').css('width'), 10);`

```

2. you need to set a width to your '.myeffect'

In your css:

`.myeffect {
 width: 100px;
 }`

3. there was no markup in the 'HTML' section of codepen, outside of the html tag that codepen probably provides by default.

In your html:

```
  <html>

  <head></head>

  <body>
    <div class="myeffect"></div>
  </body>

  </html>

```

My codepen:
<https://codepen.io/anon/pen/oegwZa>
The divs it uses are all dynamically generated and appended to the body using this method.

```
var drop = function(n, height, color) {
  $('body').append('<div class="drop" style="left:'+
                   n*15+'px;height:'+
                   height+'vh;background-color:'+
                   color+';"></div>')
    )};

```

So, you would just update the script to append to your element instead of the body element.

```
var drop = function(n, height, color) {
  $('.myeffect').append('<div class="drop" style="left:'+
                   n*15+'px;height:'+
                   height+'vh;background-color:'+
                   color+';"></div>')
    )};

```