Edit in JSFiddle

window.onload = function () {
    
    //create paper
    var paper = Raphael("canvas");
    paper.path("M100,200 L100,100");
    paper.path("M250,150 L250,100");
    paper.path("M100,200 C100,100 250,100 250,150");
}

<div id="canvas"></div>

body,html
{
    height:100%;
    margin:0;
}

#canvas 
{
    height:100%;
    background:#aaa;
}