Calculating vertical height of a SVG text

I have an array of strings. Say,

['Jan 11','Feb 11']

And i am creating a vertical text with these string like so

<text x="60" y="154" text-anchor="middle" style="text-anchor: middle; font: normal normal normal 12px/normal Helvetica, Arial; " font="12px Helvetica, Arial" stroke="none" fill="#ffffff" transform="rotate(90 59.75 150)">
<tspan>Jan 11</tspan>
</text>

After the svg has been rendered i find that the height of the text is 36px. Now is th开发者_开发百科ere a way to calculate the height of a text that will be rendered beforehand given the font-size?

You can use getBBox method to calculate dimensions of the SVG nodes.

var textNode = document.getElementsByTagName('text'),
    bbox = textNode.getBBox();

//bbox now have x, y, width and height properties