Display Image While Site loading

how do i implement this on my webflow site
div#content {
display: none;

div#loading {
top: 200 px;
margin: auto;
position: absolute;
z-index: 1000;
width: 160px;
height: 24px;
background: url(loadingimage.gif) no-repeat;
cursor: wait;
Then we will add id of div into it

your content here...
Then add the following javascript code into head section of your html page.