<style>
body{
position:relative;
}
</style>
<script>
function point(x,y){
var oDiv=document.createElement('div');
oDiv.style.position='absolute';
oDiv.style.height='5px';
oDiv.style.width='5px';
oDiv.style.backgroundColor='red';
oDiv.style.left=x+'px';
oDiv.style.top=y+'px';
document.body.appendChild(oDiv);
return oDiv;
}
function dda(x1,y1,x2,y2)
{
var dx=x1-x2,
dy=y1-y2;
var deltalx,deltaly,steps;
if(Math.abs(dx)>Math.abs(dy))
steps=Math.abs(dx);
else
steps=Math.abs(dy);
deltalx=dx/steps;
deltaly=dy/steps;
var x=x1,y=y1;
for(var i=0;i<steps;i++)
{
x+=deltalx;y+=deltaly;
point(x,y);
}
}
window.onload=function(){
dda(409,100,200,50);
}
</script>