> For the complete documentation index, see [llms.txt](https://chaoses-ib.gitbook.io/directory-opus/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://chaoses-ib.gitbook.io/directory-opus/manual/scripting/example_scripts/simple_script_function.md).

# Simple Script Function

This is an example of a [script function](/directory-opus/manual/scripting/script_functions.md) that displays the name of the largest file in the current folder, and gives you the option to select it.

To use this function you would:

* [Create a new toolbar button](/directory-opus/manual/customize/creating_your_own_buttons.md) or hotkey and [edit](/directory-opus/manual/customize/creating_your_own_buttons/editing_the_toolbar.md) it
* Click the **Advanced** button in the [command editor](/directory-opus/manual/customize/creating_your_own_buttons/command_editor.md) to switch to the [advanced command editor](/directory-opus/manual/customize/creating_your_own_buttons/command_editor/advanced_command_editor.md)
* Set the **Function** drop-down to **Script Function**

  // Set the script type to JScript to use this script. // main script entry point. clickData is a ClickData object. function OnClick(clickData) { // Initialise a variable to keep track of the largest file. largestFile = null;

  ```
    // Create an enumerator object that will let us easily enumerate the files in the current tab.
    // clickData.func is a Func object.
    // func.sourcetab is a Tab object.
    // sourcetab.files is a collection of Item objects.
    enumFiles = new Enumerator(clickData.func.sourcetab.files);

    // Enumerate the files in the tab.
    enumFiles.moveFirst();
    while (enumFiles.atEnd() == false)
    {
        // If this is the largest file encountered so far, keep track of it.
        // The file size is obtained from the Item object via its size property.
        // We use the FileSize object's cy property as this makes it easier to compare
        // two sizes numerically.
        if (largestFile == null || largestFile.size.cy < enumFiles.item().size.cy)
            largestFile = enumFiles.item();
        enumFiles.moveNext();
    }

    // Create a Dialog object to display the results.
    dlg = clickData.func.Dlg;
    if (largestFile == null)
    {
        // There were no files found, so show a warning message.
        dlg.message = "There are no files in this folder!";
        dlg.buttons = "OK";
        dlg.icon = "warn";
    }
    else
    {
        // Build the info message to report on the largest file.
        // The dialog will have two buttons, giving the user the option to select the file.
        dlg.message = "The largest file is '" + largestFile.name + "' - " + largestFile.size.fmt;
        dlg.buttons = "Select It|Cancel";
        dlg.icon = "info";
    }

    dlg.title = "Largest File Finder";
    
    // Display the dialog. if the user clicks the "Select It" button it will return 1.
    if (dlg.Show() == 1)
    {
        // Initialise and run the Select command to select the largest file.
        // This makes use of the Command object provided to the button via clickData.func.
        clickData.func.command.ClearFiles();
        clickData.func.command.AddFile(largestFile);
        clickData.func.command.RunCommand("Select FROMSCRIPT DESELECTNOMATCH MAKEVISIBLE");
    }
    else
    {
        // Not selecting a file, so make sure anything already selected is unaffected.
        clickData.func.command.deselect = false;
    }
  ```

  }