<svg xmlns="http://www.w3.org/2000/svg">

<filter id="f"/>
<g filter="url(#f)"><text>ab</text></g>

<script>

function boom()
{
    var svgtext = document.getElementsByTagName("text")[0];
    var text1 = svgtext.firstChild ;
    var text2 = text1.splitText(1);

    setTimeout(function() {
        text1.data = "c";
        svgtext.removeChild(text2);
    }, 200);
}

window.addEventListener("load", boom, false);

</script>

</svg>