Writing to external .txt files

How do you write to external .txt files so that you can read from them like this;

on (release) {
    loadText = new loadVars();
    loadText.load("hiscore.txt");
    loadText.onLoad = function(success) {
        if (success) {
            // trace(success);
            scoreBox.html = true;
            scoreBox.htmlText = this.hiScore;
        }
    };
}

then there would be a text file called hiscore.txt and it would have

hiScore; 28000

for example

you need something serverside. In the “Best of” forum i seem to remember a well written tutorial on this using PHP.