w3 school animation slide code example
Example: slide in animation css
You can use CSS3 transitions or maybe CSS3 animations to slide in an element.
For browser support: http://caniuse.com/
I made two quick examples just to show you how I mean.
CSS transition (on hover)
Demo One
Relevant Code
.wrapper:hover #slide {
transition: 1s;
left: 0;
}
In this case, Im just transitioning the position from left: -100px; to 0; with a 1s. duration. It's also possible to move the element using transform: translate();