mb-14

function setbold(IO, start, end, fontSize) {
    //Sanity checking: is the active layer a text layer?
    var activeLayer = app.activeDocument.activeLayer;
    if (activeLayer.kind == LayerKind.TEXT) {
        //More checking: does the text layer have content, and are start and end set to reasonable values?
        if ((activeLayer.textItem.contents != "") && (start >= 0) && (end <= activeLayer.textItem.contents.length)) {
            //The indentation that the Script Listerner gives you is weird, but it’s useful.
            var idsetd = app.charIDToTypeID("setd");
            var action = new ActionDescriptor();
            var idnull = app.charIDToTypeID("null");