This question is focused on HTML, CSS, and Javascript.
Customizing a scrollbar in a way that works consistently across different browsers is a challenge that can be addressed through javascript.
The following resources explore various CSS techniques:
How to utilize scroll bar images
Replacing the default scrollbar with a custom one in a small text area
Styling scrollbars
To implement this using javascript, create an absolute div inside a relative div like so:
<div id="container">
<div id="scrollarea">
</div>
<a id="up-arrow"> </a>
<a id="down-arrow"> </a>
</div>
Add some CSS properties:
#container
{
position:relative;
width:300px;
height:400px;
overflow:hidden;
}
#scrollarea
{
position:absolute;
top:0px;
overflow:hidden;
height:800px;
width:280px;
}
#up-arrow
{
background-image:something;
width:20px;
height:20px;
display:block;
position:absolute;
right:0px;
top:0px;
}
And include the following javascript (using jQuery):
var currentScroll=0;
$("#up-arrow").click(function(){
currentScroll+=20;
$("#scrollarea").css("top",currentScroll+"px");
});
$("#down-arrow").click(function(){
currentScroll-=20;
$("#scrollarea").css("top",currentScroll+"px");
});