Autosize an SVG?

Question

Here is a code demo

I have a SVG with an unknown height. I can figure it out after I load in json and use javascript+math but is there any css I can use to dynamically size it?

css:

svg {
  width: 500px;
  height: 9000px;
}
.tabme {
  border:3px solid red;
  height: 200px;
   overflow:scroll;
}

html:

<div class="tabme">
  <div id="Chart">
    <div class="chartbody" />
    <svg>
      <rect width="190" y="0" height="16" x="175" />
      <rect width="190" y="20" height="16" x="175" />
      <rect width="190" y="40" height="16" x="175" />
      <rect width="190" y="60" height="16" x="175" />
      <rect width="190" y="80" height="16" x="175" />
      <rect width="190" y="100" height="16" x="175" />
      <rect width="190" y="120" height="16" x="175" />
      <rect width="190" y="140" height="16" x="175" />
      <rect width="190" y="160" height="16" x="175" />
      <rect width="190" y="180" height="16" x="175" />
      <rect width="190" y="200" height="16" x="175" />
      <rect width="190" y="220" height="16" x="175" />
      <rect width="190" y="240" height="16" x="175" />
      <rect width="190" y="260" height="16" x="175" />
      <rect width="190" y="280" height="16" x="175" />
      <rect width="190" y="300" height="16" x="175" />
    </svg>
  </div>
</div>

Answer 1

If the SVG element does not have any width and height attributes, then the width/height should be calculated according to the CSS specs, as pointed out by Robert Longson. However, those values will not reflect the proper dimensions of the SVG's content. You can find out the proper dimensions and placement using getBBox():

// Javascript to run after document load
var svg = document.getElementsByTagName("svg")[0];
var bbox = svg.getBBox();
svg.setAttribute("width", bbox.width + "px");
svg.setAttribute("height", bbox.height + "px");
svg.setAttribute("viewBox", `${bbox.x} ${bbox.y} ${bbox.width} ${bbox.height}`);

<svg xmlns="http://www.w3.org/2000/svg" style="background-color: red">
  <rect x="30" y="40" width="50" height="60"/>
</svg>