请问怎样设置画线的颜色?

Question

以下是用来画线的,我想把线的颜色设为红色,请问怎样设? <script language="javascript">var Working=false;
var points = [];
var lastPoint = {x:0,y:0};document.body.scrollLeft=document.body.offsetWidth;function drawCanvas()
{
var arr = eval(req.responseText);
      var x1 = arr[0];
var y1 = arr[1];
if(!Working){
document.getElementById("show").style.display="none";
Working=true;
lastPoint.x = x1;
lastPoint.y = y1;
points.push( {x:x1,y:y1} );}else{
var s='<v:line from="'+lastPoint.x+','+lastPoint.y+'" to="'+x1+','+y1+'" style="color:red;position:absolute;left:0px;top:0px;"></v:line>';
lastPoint.x = x1;
lastPoint.y = y1;
points.push( {x:x1,y:y1} );var o=document.createElement(s);
document.body.insertAdjacentElement('BeforeEnd',o);
}
}
</script>