Setting an Active Document

Question

I am trying to set a particular doc as the active document after it and another one is opened after the user browses for two files.
Below I have a function that occurs when a button is pressed. Most of the code is for the file browser that is platform specific. In the middle of this block of code, the document that is chosen will set the path of a variable that is declared outside of the function. That outside-declared variable is called "singTemp". At the very last line of the code below, I added the code that I have seen in an example. The active document property is set to the value of the variable "singTemp". Thanks for your help.
var singTemp;
defineVars.inputDataPnl.singleTemplateBtn.onClick = function singleTemplateSelect() {
var SingleTemplate = getDocFile();
if (SingleTemplate == null) return;
function getDocFile() {
// cross-platform document file selector
if (File.fs == "Windows") {
var select = "Photoshop File :*.psd, *.PSD"
} else {
var select = filterFiles
SingleTemplate = File.openDialog("Choose the Single Mugshot Key Template", select);
if (SingleTemplate == null) {
// No further action
}else {
singTemp = new File(SingleTemplate);
return SingleTemplate;
function filterFiles(file) {
while (file.alias) {
file = file.resolve();
if (file == null) { return false }
if (file.constructor.name == "Folder") return true
var extn = file.name.toLowerCase().slice(file.name.lastIndexOf("."));
switch (extn) {
case ".psd" : return true;
case ".PSD" : return true;
default : return false;
app.activeDocument = singTemp;

Answer 1

Thanks very much! Now to try to get my head around all this...