D3 - using SVG Bounding Box to get the "automatic padding"

<!DOCTYPE html>
<html>
  <head>
    <script type="text/javascript" src="https://cdn.jsdelivr.net/npm/d3@2.1.3/d3.js"></script>
    <style>
        path { fill:none;stroke:black}
    </style>
   <head>.
<body>
    
<script type="text/javascript">
    
    var w=960,
         h=450;
    svg=d3.select("body").append("svg:svg").attr("height",h).attr("width",w)
    x = d3.scale.linear().range([0, w]).domain([0,100]),
    y = d3.scale.linear().range([h, 0])
    
    xAxis = d3.svg.axis().scale(x).tickSize(-h).ticks(5),
    yAxis = d3.svg.axis().scale(y).tickSize(-w).orient("left");
    
    var domain=100
    
    // Add the x-axis.
    x_svg=svg.append("svg:g")
        .attr("class", "x axis")
        .attr("transform", "translate(0," + h + ")")
        .call(xAxis)

// Add the y-axis.
    y_svg=axis = svg.append("svg:g")
        .attr("class", "y axis")
        
        
    // Add y-title - we position it when we change the domain
    y_title = svg.append("svg:g")
                .append("svg:text")
                    .text("This is the title of the y-axis")
                    .style("text-anchor","middle")
    
    // add Chart Title
    svg.append("svg:text")
        
        .text("THIS IS THE CHART TITLE")
        .attr("x",w/2)
        .attr("dy","-1em")
        .style("text-anchor","middle")
        
    // add x-title
    svg.append("svg:text")
        .text("And here is the x-title")
        .attr("x",w/2)
        .attr("y",h)
        .attr("dy","2em")
        .style("text-anchor","middle")
    
    function changeDomain() {
        domain = (domain==100) ? 999999999 : 100;
        y.domain([0,domain])
        x.domain([0,domain])
        y_svg.call(yAxis)
        x_svg.call(xAxis)
        
        // update the location of y_title        
        y_title.attr("transform","translate("+
                    (parseFloat(y_svg[0][0].getBBox().x)-10)+" "
                    +h/2+") rotate(-90)")
        
        //update the viewBox to capture the svg bbox
        bbox = svg[0][0].getBBox()
        svg.attr("viewBox",bbox.x+" "+bbox.y+" "+bbox.width+" "+bbox.height)
    }

changeDomain();
    setInterval(changeDomain,1000);
    
</script>
</body>

Modified http://mbostock.github.com/d3/d3.js?2.0.0 to a secure url

https://mbostock.github.com/d3/d3.js?2.0.0