Get pixel length of String in Svg

Question

I'm currently working with SVG. I need to know the string length in pixels in order to do some alignment. How can I do to get the length of a string in pixel ?

Update: Thanks to nrabinowitz. Based on his help, I can now get the length of dynamic-added text. Here is an example:

<svg id="main"      xmlns="http://www.w3.org/2000/svg"      xmlns:xlink="http://www.w3.org/1999/xlink"     version="1.1"      width="1020"     height="620"      viewBox="0 0 1020 620"     onload="startup(evt)">  <script>     <![CDATA[         var startup = function (evt) {             var width;             var svgNS = "http://www.w3.org/2000/svg";             var txtNode = document.createTextNode("Hello");             text = document.createElementNS(svgNS,"text");              text.setAttributeNS(null,"x",100);             text.setAttributeNS(null,"y",100);             text.setAttributeNS(null,"fill","black");             text.appendChild(txtNode);                                                           width = text.getComputedTextLength();                            alert(" Width before appendChild: "+  width);                                    document.getElementById("main").appendChild(text);             width = text.getComputedTextLength();             alert(" Width after appendChild: "+  width)             document.getElementById("main").removeChild(text);                       }            //]]> </script> </svg> 

Answer 1

I've been wondering this too, and I was pleasantly surprised to find that, according to the SVG spec, there is a specific function to return this info: getComputedTextLength()

// access the text element you want to measure var el = document.getElementsByTagName('text')[3]; el.getComputedTextLength(); // returns a pixel integer 

Working fiddle (only tested in Chrome): http://jsfiddle.net/jyams/