function getElementsByClassName(className, tag, elm) {
var testClass = new RegExp("(^|\\\\s)" + className + "(\\\\s|$)");
var tag = tag || "*";
var elm = elm || document;
var elements = (tag == "*" && elm.all)? elm.all : elm.getElementsByTagName(tag);
var returnElements = [];
var current;
var length = elements.length;
for(var i=0; i<length; i++){
current = elements[i];
if(testClass.test(current.className)){
returnElements.push(current);
}
}
return returnElements;
}

function roundedCorners(parentElement) {
var classArray = getElementsByClassName('image_left', 'span', parentElement);
for (var i = 0; i < classArray.length; i++) {
classContent = classArray[i].innerHTML;
classArray[i].innerHTML = classContent + '<span class="tr"></span><span class="tl"></span><span class="br"></span><span class="bl"></span>';
}
var classArray = getElementsByClassName('image_right', 'span', parentElement);
for (var i = 0; i < classArray.length; i++) {
classContent = classArray[i].innerHTML;
classArray[i].innerHTML = classContent + '<span class="tr"></span><span class="tl"></span><span class="br"></span><span class="bl"></span>';
}
}