javascript - HTML line drawing without canvas (just JS)

Question

I am trying to use HTML and draw a line on a page.

From everything I have read suggests HTML5 canvas tag is the best to use, but I need the line to connect to something on the page which is not in a canvas tag so canvas is not good for me (want/need to use native JS).

I have written (from something I found) a function which does what i need but problem is once line appears, everything else of page disappears.

I found that every time I change the style in JavaScript everything but the shape disappears.

Deleting "document.write" ends with nothing disappearing.

function draw(ax, ay, bx, by) {
    var n, widthLine, i, x, y;
    widthLine = 1;
    if (Math.abs(ax - bx) > Math.abs(ay - by)) {
        if (ax > bx) {
            n = ax;
            ax = bx;
            bx = n;

            n = ay;
            ay = by;
            by = n;
        }
        n = (by - ay) / (bx - ax);

        for (i = ax; i <= bx; i++) {
            x = i;
            y = Math.round(ay + m * (x - ax));
            document.write("<div style='height:" + lineWidth + "px;width:" + widthLine + "px;background-color:black;position:absolute;top:" + y + "px;left:" + x + "px;'></div>");
        }
    } else {
        if (ay > by) {
            n = ax;
            ax = bx;
            bx = n;

            n = ay;
            ay = by;
            by = n;
        }
        n = (bx - ax) / (by - ay);

        for (i = ay; i <= by; i++) {
            y = i;
            x = Math.round(ax + n * (y - ay));
            document.write("<div style='height:" + lineWidth + "px;width:" + lineWidth + "px;background-color:black;position:absolute;top:" + y + "px;left:" + x + "px;'></div>");
        }
    }
}

Answer 1

A quick fix.

The below function gets the coords of the line and then draws it.

It works by using a long and thin div element. The rotation angle and length are calculated.

Should work across all browsers (hopefully even IE).

function linedraw(ax,ay,bx,by)
{
    if(ay>by)
    {
        bx=ax+bx;  
        ax=bx-ax;
        bx=bx-ax;
        by=ay+by;  
        ay=by-ay;  
        by=by-ay;
    }
    var calc=Math.atan((ay-by)/(bx-ax));
    calc=calc*180/Math.PI;
    var length=Math.sqrt((ax-bx)*(ax-bx)+(ay-by)*(ay-by));
    document.body.innerHTML += "<div id='line' style='height:" + length + "px;width:1px;background-color:black;position:absolute;top:" + (ay) + "px;left:" + (ax) + "px;transform:rotate(" + calc + "deg);-ms-transform:rotate(" + calc + "deg);transform-origin:0% 0%;-moz-transform:rotate(" + calc + "deg);-moz-transform-origin:0% 0%;-webkit-transform:rotate(" + calc  + "deg);-webkit-transform-origin:0% 0%;-o-transform:rotate(" + calc + "deg);-o-transform-origin:0% 0%;'></div>"
}